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20920571 = 729257401
BaseRepresentation
bin100111111001…
…1100011111011
31110100212121222
41033303203323
520323424241
62024222255
7342551630
oct117634373
943325558
1020920571
1110899a31
12700a98b
134446449
142ac8187
151c83a4b
hex13f38fb

20920571 has 16 divisors (see below), whose sum is σ = 24891840. Its totient is φ = 17203200.

The previous prime is 20920541. The next prime is 20920589. The reversal of 20920571 is 17502902.

It is a de Polignac number, because none of the positive numbers 2k-20920571 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20920571.

It is not an unprimeable number, because it can be changed into a prime (20920511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51971 + ... + 52371.

It is an arithmetic number, because the mean of its divisors is an integer number (1555740).

Almost surely, 220920571 is an apocalyptic number.

20920571 is a deficient number, since it is larger than the sum of its proper divisors (3971269).

20920571 is a wasteful number, since it uses less digits than its factorization.

20920571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694.

The product of its (nonzero) digits is 1260, while the sum is 26.

The square root of 20920571 is about 4573.9010702025. The cubic root of 20920571 is about 275.5441391373.

The spelling of 20920571 in words is "twenty million, nine hundred twenty thousand, five hundred seventy-one".

Divisors: 1 7 29 203 257 401 1799 2807 7453 11629 52171 81403 103057 721399 2988653 20920571