215951616 has 144 divisors (see below), whose sum is σ = 645904000. Its totient is φ = 71165952.

The previous prime is 215951609. The next prime is 215951621. The reversal of 215951616 is 616159512.

215951616 is a `hidden beast` number, since 2 + 1 + 595 + 1 + 61 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×215951616² = 93270200906022912, which contains 22 as substring.

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

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, 1085085 + ... + 1085283.

Almost surely, 2^215951616 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 215951616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (322952000).

215951616 is an abundant number, since it is smaller than the sum of its proper divisors (429952384).

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

215951616 is a wasteful number, since it uses less digits than its factorization.

215951616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381 (or 361 counting only the distinct ones).

The product of its digits is 16200, while the sum is 36.

The square root of 215951616 is about 14695.2923074024. The cubic root of 215951616 is about 599.9551966545.

The spelling of 215951616 in words is "two hundred fifteen million, nine hundred fifty-one thousand, six hundred sixteen".