215421156 has 18 divisors (see below), whose sum is σ = 544536902. Its totient is φ = 71807040.

The previous prime is 215421137. The next prime is 215421179. The reversal of 215421156 is 651124512.

215421156 is a `hidden beast` number, since 2 + 1 + 542 + 115 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 200675556 + 14745600 = 14166^2 + 3840^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2991925 + ... + 2991996.

Almost surely, 2^215421156 is an apocalyptic number.

It is an amenable number.

215421156 is an abundant number, since it is smaller than the sum of its proper divisors (329115746).

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

215421156 is a wasteful number, since it uses less digits than its factorization.

215421156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5983931 (or 5983926 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 215421156 is about 14677.2325729342. The cubic root of 215421156 is about 599.4635538522.

Adding to 215421156 its reverse (651124512), we get a palindrome (866545668).

The spelling of 215421156 in words is "two hundred fifteen million, four hundred twenty-one thousand, one hundred fifty-six".