636897428 has 12 divisors (see below), whose sum is σ = 1144694292. Its totient is φ = 309841920.

The previous prime is 636897427. The next prime is 636897431. The reversal of 636897428 is 824798636.

It can be written as a sum of positive squares in 2 ways, for example, as 443186704 + 193710724 = 21052^2 + 13918^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 636897428.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636897427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2151533 + ... + 2151828.

It is an arithmetic number, because the mean of its divisors is an integer number (95391191).

Almost surely, 2^636897428 is an apocalyptic number.

It is an amenable number.

636897428 is a deficient number, since it is larger than the sum of its proper divisors (507796864).

636897428 is a wasteful number, since it uses less digits than its factorization.

636897428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4303402 (or 4303400 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 53.

The square root of 636897428 is about 25236.8268211358. The cubic root of 636897428 is about 860.3790595076.

It can be divided in two parts, 63689 and 7428, that added together give a palindrome (71117).

The spelling of 636897428 in words is "six hundred thirty-six million, eight hundred ninety-seven thousand, four hundred twenty-eight".