215661628 has 48 divisors (see below), whose sum is σ = 488965120. Its totient is φ = 80823744.

The previous prime is 215661601. The next prime is 215661653. The reversal of 215661628 is 826166512.

It is a super-2 number, since 2×215661628² = 93019875583220768, which 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 15 ways as a sum of consecutive naturals, for example, 8676 + ... + 22507.

Almost surely, 2^215661628 is an apocalyptic number.

215661628 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

215661628 is an abundant number, since it is smaller than the sum of its proper divisors (273303492).

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

215661628 is a wasteful number, since it uses less digits than its factorization.

215661628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31226 (or 31224 counting only the distinct ones).

The product of its digits is 34560, while the sum is 37.

The square root of 215661628 is about 14685.4222955964. The cubic root of 215661628 is about 599.6865288475.

The spelling of 215661628 in words is "two hundred fifteen million, six hundred sixty-one thousand, six hundred twenty-eight".