1997168861520 has 240 divisors, whose sum is σ = 7757679226752. Its totient is φ = 450995696640.

The previous prime is 1997168861449. The next prime is 1997168861537. The reversal of 1997168861520 is 251688617991.

1997168861520 is a `hidden beast` number, since 1 + 9 + 9 + 7 + 1 + 6 + 8 + 8 + 615 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×1997168861520² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1968811 + ... + 2805450.

Almost surely, 2^{1997168861520} is an apocalyptic number.

1997168861520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1997168861520 is an abundant number, since it is smaller than the sum of its proper divisors (5760510365232).

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

1997168861520 is a wasteful number, since it uses less digits than its factorization.

1997168861520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4774370 (or 4774361 counting only the distinct ones).

The product of its (nonzero) digits is 13063680, while the sum is 63.

The spelling of 1997168861520 in words is "one trillion, nine hundred ninety-seven billion, one hundred sixty-eight million, eight hundred sixty-one thousand, five hundred twenty".