216697131553961 has 2 divisors, whose sum is σ = 216697131553962. Its totient is φ = 216697131553960.

The previous prime is 216697131553957. The next prime is 216697131553979. The reversal of 216697131553961 is 169355131796612.

216697131553961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 177997783579561 + 38699347974400 = 13341581^2 + 6220880^2 .

It is a cyclic number.

It is not a de Polignac number, because 216697131553961 - 2² = 216697131553957 is a prime.

It is not a weakly prime, because it can be changed into another prime (216697131253961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108348565776980 + 108348565776981.

It is an arithmetic number, because the mean of its divisors is an integer number (108348565776981).

Almost surely, 2^{216697131553961} is an apocalyptic number.

It is an amenable number.

216697131553961 is a deficient number, since it is larger than the sum of its proper divisors (1).

216697131553961 is an equidigital number, since it uses as much as digits as its factorization.

216697131553961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55112400, while the sum is 65.

The spelling of 216697131553961 in words is "two hundred sixteen trillion, six hundred ninety-seven billion, one hundred thirty-one million, five hundred fifty-three thousand, nine hundred sixty-one".