90090997 has 2 divisors, whose sum is σ = 90090998. Its totient is φ = 90090996.

The previous prime is 90090983. The next prime is 90091013. The reversal of 90090997 is 79909009.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51638596 + 38452401 = 7186^2 + 6201^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90090997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90090097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45045498 + 45045499.

It is an arithmetic number, because the mean of its divisors is an integer number (45045499).

Almost surely, 2^90090997 is an apocalyptic number.

It is an amenable number.

90090997 is a deficient number, since it is larger than the sum of its proper divisors (1).

90090997 is an equidigital number, since it uses as much as digits as its factorization.

90090997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45927, while the sum is 43.

The square root of 90090997 is about 9491.6277318487. The cubic root of 90090997 is about 448.2914587400.

The spelling of 90090997 in words is "ninety million, ninety thousand, nine hundred ninety-seven".