691430256 has 280 divisors, whose sum is σ = 2327355504. Its totient is φ = 196577280.

The previous prime is 691430227. The next prime is 691430287. The reversal of 691430256 is 652034196.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 691430256.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 2181010 + ... + 2181326.

Almost surely, 2^691430256 is an apocalyptic number.

691430256 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691430256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1163677752).

691430256 is an abundant number, since it is smaller than the sum of its proper divisors (1635925248).

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

691430256 is a wasteful number, since it uses less digits than its factorization.

691430256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 371 (or 350 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 691430256 is about 26295.0614374639. The cubic root of 691430256 is about 884.2657282131.

The spelling of 691430256 in words is "six hundred ninety-one million, four hundred thirty thousand, two hundred fifty-six".