90131621 has 2 divisors, whose sum is σ = 90131622. Its totient is φ = 90131620.

The previous prime is 90131551. The next prime is 90131627. The reversal of 90131621 is 12613109.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49350625 + 40780996 = 7025^2 + 6386^2 .

It is an emirp because it is prime and its reverse (12613109) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90131621 - 2²² = 85937317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90131627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45065810 + 45065811.

It is an arithmetic number, because the mean of its divisors is an integer number (45065811).

Almost surely, 2^90131621 is an apocalyptic number.

It is an amenable number.

90131621 is a deficient number, since it is larger than the sum of its proper divisors (1).

90131621 is an equidigital number, since it uses as much as digits as its factorization.

90131621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 90131621 is about 9493.7674818799. The cubic root of 90131621 is about 448.3588300875.

The spelling of 90131621 in words is "ninety million, one hundred thirty-one thousand, six hundred twenty-one".