215694121 has 2 divisors, whose sum is σ = 215694122. Its totient is φ = 215694120.

The previous prime is 215694119. The next prime is 215694163. The reversal of 215694121 is 121496512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 149108521 + 66585600 = 12211^2 + 8160^2 .

It is a cyclic number.

It is not a de Polignac number, because 215694121 - 2¹ = 215694119 is a prime.

Together with 215694119, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (215694191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107847060 + 107847061.

It is an arithmetic number, because the mean of its divisors is an integer number (107847061).

Almost surely, 2^215694121 is an apocalyptic number.

It is an amenable number.

215694121 is a deficient number, since it is larger than the sum of its proper divisors (1).

215694121 is an equidigital number, since it uses as much as digits as its factorization.

215694121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 31.

The square root of 215694121 is about 14686.5285551079. The cubic root of 215694121 is about 599.7166449079.

The spelling of 215694121 in words is "two hundred fifteen million, six hundred ninety-four thousand, one hundred twenty-one".