90856813 has 2 divisors, whose sum is σ = 90856814. Its totient is φ = 90856812.

The previous prime is 90856741. The next prime is 90856817. The reversal of 90856813 is 31865809.

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., 90212004 + 644809 = 9498^2 + 803^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90856813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90856817) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45428406 + 45428407.

It is an arithmetic number, because the mean of its divisors is an integer number (45428407).

Almost surely, 2^90856813 is an apocalyptic number.

It is an amenable number.

90856813 is a deficient number, since it is larger than the sum of its proper divisors (1).

90856813 is an equidigital number, since it uses as much as digits as its factorization.

90856813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 90856813 is about 9531.8840215353. The cubic root of 90856813 is about 449.5581061260.

The spelling of 90856813 in words is "ninety million, eight hundred fifty-six thousand, eight hundred thirteen".