685437538428 has 18 divisors (see below), whose sum is σ = 1732633777784. Its totient is φ = 228479179464.

The previous prime is 685437538397. The next prime is 685437538493. The reversal of 685437538428 is 824835734586.

685437538428 is a `hidden beast` number, since 6 + 8 + 54 + 3 + 7 + 538 + 42 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×685437538428² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9519965776 + ... + 9519965847.

Almost surely, 2^685437538428 is an apocalyptic number.

It is an amenable number.

685437538428 is an abundant number, since it is smaller than the sum of its proper divisors (1047196239356).

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

685437538428 is a wasteful number, since it uses less digits than its factorization.

685437538428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19039931633 (or 19039931628 counting only the distinct ones).

The product of its digits is 154828800, while the sum is 63.

The spelling of 685437538428 in words is "six hundred eighty-five billion, four hundred thirty-seven million, five hundred thirty-eight thousand, four hundred twenty-eight".