990788531 has 2 divisors, whose sum is σ = 990788532. Its totient is φ = 990788530.

The previous prime is 990788507. The next prime is 990788537. The reversal of 990788531 is 135887099.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 990788531 - 2¹⁴ = 990772147 is a prime.

It is a super-2 number, since 2×990788531² = 1963323826322275922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 990788531.

It is not a weakly prime, because it can be changed into another prime (990788537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495394265 + 495394266.

It is an arithmetic number, because the mean of its divisors is an integer number (495394266).

Almost surely, 2^990788531 is an apocalyptic number.

990788531 is a deficient number, since it is larger than the sum of its proper divisors (1).

990788531 is an equidigital number, since it uses as much as digits as its factorization.

990788531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 544320, while the sum is 50.

The square root of 990788531 is about 31476.7935311080. The cubic root of 990788531 is about 996.9200338811.

The spelling of 990788531 in words is "nine hundred ninety million, seven hundred eighty-eight thousand, five hundred thirty-one".