215820972 has 36 divisors (see below), whose sum is σ = 553237776. Its totient is φ = 70926240.

The previous prime is 215820919. The next prime is 215820973. The reversal of 215820972 is 279028512.

215820972 is a `hidden beast` number, since 2 + 1 + 582 + 0 + 9 + 72 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is not an unprimeable number, because it can be changed into a prime (215820973) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39663 + ... + 44774.

It is an arithmetic number, because the mean of its divisors is an integer number (15367716).

Almost surely, 2^215820972 is an apocalyptic number.

It is an amenable number.

215820972 is an abundant number, since it is smaller than the sum of its proper divisors (337416804).

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

215820972 is a wasteful number, since it uses less digits than its factorization.

215820972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84518 (or 84513 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 215820972 is about 14690.8465378956. The cubic root of 215820972 is about 599.8341875146.

The spelling of 215820972 in words is "two hundred fifteen million, eight hundred twenty thousand, nine hundred seventy-two".