691412638 has 48 divisors (see below), whose sum is σ = 1234220544. Its totient is φ = 289578240.

The previous prime is 691412633. The next prime is 691412639. The reversal of 691412638 is 836214196.

It is a super-2 number, since 2×691412638² = 956102871972238088, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 691412638.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691412633) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 908178 + ... + 908938.

It is an arithmetic number, because the mean of its divisors is an integer number (25712928).

Almost surely, 2^691412638 is an apocalyptic number.

691412638 is a deficient number, since it is larger than the sum of its proper divisors (542807906).

691412638 is a wasteful number, since it uses less digits than its factorization.

691412638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 977 (or 970 counting only the distinct ones).

The product of its digits is 62208, while the sum is 40.

The square root of 691412638 is about 26294.7264294573. The cubic root of 691412638 is about 884.2582176335.

The spelling of 691412638 in words is "six hundred ninety-one million, four hundred twelve thousand, six hundred thirty-eight".