90664405421 has 2 divisors, whose sum is σ = 90664405422. Its totient is φ = 90664405420.

The previous prime is 90664405399. The next prime is 90664405453. The reversal of 90664405421 is 12450446609.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80026752100 + 10637653321 = 282890^2 + 103139^2 .

It is a cyclic number.

It is not a de Polignac number, because 90664405421 - 2²⁶ = 90597296557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90664405121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45332202710 + 45332202711.

It is an arithmetic number, because the mean of its divisors is an integer number (45332202711).

Almost surely, 2^90664405421 is an apocalyptic number.

It is an amenable number.

90664405421 is a deficient number, since it is larger than the sum of its proper divisors (1).

90664405421 is an equidigital number, since it uses as much as digits as its factorization.

90664405421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 207360, while the sum is 41.

The spelling of 90664405421 in words is "ninety billion, six hundred sixty-four million, four hundred five thousand, four hundred twenty-one".