681995637 has 12 divisors (see below), whose sum is σ = 994312800. Its totient is φ = 450413928.

The previous prime is 681995627. The next prime is 681995641. The reversal of 681995637 is 736599186.

681995637 is a `hidden beast` number, since 68 + 19 + 9 + 563 + 7 = 666.

It is not a de Polignac number, because 681995637 - 2⁴ = 681995621 is a prime.

It is a super-3 number, since 3×681995637³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681995627) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 353137 + ... + 355062.

It is an arithmetic number, because the mean of its divisors is an integer number (82859400).

Almost surely, 2^681995637 is an apocalyptic number.

It is an amenable number.

681995637 is a deficient number, since it is larger than the sum of its proper divisors (312317163).

681995637 is a wasteful number, since it uses less digits than its factorization.

681995637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708312 (or 708309 counting only the distinct ones).

The product of its digits is 2449440, while the sum is 54.

The square root of 681995637 is about 26115.0461803153. The cubic root of 681995637 is about 880.2253370084.

The spelling of 681995637 in words is "six hundred eighty-one million, nine hundred ninety-five thousand, six hundred thirty-seven".