215021961 has 72 divisors (see below), whose sum is σ = 396923072. Its totient is φ = 109771200.

The previous prime is 215021951. The next prime is 215021977. The reversal of 215021961 is 169120512.

215021961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 215021961 - 2⁵ = 215021929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (215021951) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 510531 + ... + 510951.

Almost surely, 2^215021961 is an apocalyptic number.

215021961 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

215021961 is a deficient number, since it is larger than the sum of its proper divisors (181901111).

215021961 is a wasteful number, since it uses less digits than its factorization.

215021961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523 (or 509 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 215021961 is about 14663.6271433776. The cubic root of 215021961 is about 599.0930380575.

The spelling of 215021961 in words is "two hundred fifteen million, twenty-one thousand, nine hundred sixty-one".