215661456 has 120 divisors (see below), whose sum is σ = 656603064. Its totient is φ = 65802240.

The previous prime is 215661449. The next prime is 215661497. The reversal of 215661456 is 654166512.

It can be written as a sum of positive squares in 4 ways, for example, as 31136400 + 184525056 = 5580^2 + 13584^2 .

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 215661456.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 89386 + ... + 91766.

Almost surely, 2^215661456 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 215661456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (328301532).

215661456 is an abundant number, since it is smaller than the sum of its proper divisors (440941608).

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

215661456 is a wasteful number, since it uses less digits than its factorization.

215661456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2449 (or 2440 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 215661456 is about 14685.4164394477. The cubic root of 215661456 is about 599.6863694217.

The spelling of 215661456 in words is "two hundred fifteen million, six hundred sixty-one thousand, four hundred fifty-six".