215401961 has 2 divisors, whose sum is σ = 215401962. Its totient is φ = 215401960.

The previous prime is 215401931. The next prime is 215401973. The reversal of 215401961 is 169104512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 130393561 + 85008400 = 11419^2 + 9220^2 .

It is a cyclic number.

It is not a de Polignac number, because 215401961 - 2⁶ = 215401897 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (215401931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107700980 + 107700981.

It is an arithmetic number, because the mean of its divisors is an integer number (107700981).

Almost surely, 2^215401961 is an apocalyptic number.

It is an amenable number.

215401961 is a deficient number, since it is larger than the sum of its proper divisors (1).

215401961 is an equidigital number, since it uses as much as digits as its factorization.

215401961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 215401961 is about 14676.5786544412. The cubic root of 215401961 is about 599.4457483514.

The spelling of 215401961 in words is "two hundred fifteen million, four hundred one thousand, nine hundred sixty-one".