997857156647 has 16 divisors (see below), whose sum is σ = 1111230193920. Its totient is φ = 889819257600.

The previous prime is 997857156511. The next prime is 997857156649. The reversal of 997857156647 is 746651758799.

It is not a de Polignac number, because 997857156647 - 2¹⁰ = 997857155623 is a prime.

It is a super-3 number, since 3×997857156647³ (a number of 37 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997857156649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1946504 + ... + 2405117.

It is an arithmetic number, because the mean of its divisors is an integer number (69451887120).

Almost surely, 2^997857156647 is an apocalyptic number.

997857156647 is a deficient number, since it is larger than the sum of its proper divisors (113373037273).

997857156647 is a wasteful number, since it uses less digits than its factorization.

997857156647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4352234.

The product of its digits is 800150400, while the sum is 74.

The spelling of 997857156647 in words is "nine hundred ninety-seven billion, eight hundred fifty-seven million, one hundred fifty-six thousand, six hundred forty-seven".