1997857901172 has 96 divisors (see below), whose sum is σ = 5568942355200. Its totient is φ = 556894141440.

The previous prime is 1997857901129. The next prime is 1997857901197. The reversal of 1997857901172 is 2711097587991.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5750613 + ... + 6088124.

It is an arithmetic number, because the mean of its divisors is an integer number (58009816200).

Almost surely, 2^{1997857901172} is an apocalyptic number.

1997857901172 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1997857901172 is an abundant number, since it is smaller than the sum of its proper divisors (3571084454028).

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

1997857901172 is a wasteful number, since it uses less digits than its factorization.

1997857901172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11838806 (or 11838790 counting only the distinct ones).

The product of its (nonzero) digits is 20003760, while the sum is 66.

The spelling of 1997857901172 in words is "one trillion, nine hundred ninety-seven billion, eight hundred fifty-seven million, nine hundred one thousand, one hundred seventy-two".