215638664401 has 2 divisors, whose sum is σ = 215638664402. Its totient is φ = 215638664400.

The previous prime is 215638664387. The next prime is 215638664473. The reversal of 215638664401 is 104466836512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 192580545600 + 23058118801 = 438840^2 + 151849^2 .

It is a cyclic number.

It is not a de Polignac number, because 215638664401 - 2¹³ = 215638656209 is a prime.

It is not a weakly prime, because it can be changed into another prime (215638661401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107819332200 + 107819332201.

It is an arithmetic number, because the mean of its divisors is an integer number (107819332201).

Almost surely, 2^215638664401 is an apocalyptic number.

It is an amenable number.

215638664401 is a deficient number, since it is larger than the sum of its proper divisors (1).

215638664401 is an equidigital number, since it uses as much as digits as its factorization.

215638664401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 829440, while the sum is 46.

The spelling of 215638664401 in words is "two hundred fifteen billion, six hundred thirty-eight million, six hundred sixty-four thousand, four hundred one".