90172813 has 2 divisors, whose sum is σ = 90172814. Its totient is φ = 90172812.

The previous prime is 90172807. The next prime is 90172853. The reversal of 90172813 is 31827109.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 89359209 + 813604 = 9453^2 + 902^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90172813 is a prime.

It is a super-2 number, since 2×90172813² = 16262272408665938, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90172853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45086406 + 45086407.

It is an arithmetic number, because the mean of its divisors is an integer number (45086407).

Almost surely, 2^90172813 is an apocalyptic number.

It is an amenable number.

90172813 is a deficient number, since it is larger than the sum of its proper divisors (1).

90172813 is an equidigital number, since it uses as much as digits as its factorization.

90172813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 90172813 is about 9495.9366573288. The cubic root of 90172813 is about 448.4271227463.

The spelling of 90172813 in words is "ninety million, one hundred seventy-two thousand, eight hundred thirteen".