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1997121564 = 2232518910691
BaseRepresentation
bin111011100001001…
…1010100000011100
312011011221021202100
41313002122200130
513042230342224
6530101125100
7100330152564
oct16702324034
95134837670
101997121564
11935360a99
124789b9790
1325a9aa149
1414d349da4
15ba4e4ac9
hex7709a81c

1997121564 has 36 divisors (see below), whose sum is σ = 5049724680. Its totient is φ = 665516640.

The previous prime is 1997121551. The next prime is 1997121589. The reversal of 1997121564 is 4651217991.

1997121564 is a `hidden beast` number, since 19 + 9 + 71 + 2 + 1 + 564 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 181459 + ... + 192149.

It is an arithmetic number, because the mean of its divisors is an integer number (140270130).

Almost surely, 21997121564 is an apocalyptic number.

It is an amenable number.

1997121564 is an abundant number, since it is smaller than the sum of its proper divisors (3052603116).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1997121564 is a wasteful number, since it uses less digits than its factorization.

1997121564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15890 (or 15885 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The square root of 1997121564 is about 44689.1660696415. The cubic root of 1997121564 is about 1259.3163260077.

The spelling of 1997121564 in words is "one billion, nine hundred ninety-seven million, one hundred twenty-one thousand, five hundred sixty-four".

Divisors: 1 2 3 4 6 9 12 18 36 5189 10378 10691 15567 20756 21382 31134 32073 42764 46701 62268 64146 93402 96219 128292 186804 192438 384876 55475599 110951198 166426797 221902396 332853594 499280391 665707188 998560782 1997121564