990571979 has 2 divisors, whose sum is σ = 990571980. Its totient is φ = 990571978.

The previous prime is 990571969. The next prime is 990571987. The reversal of 990571979 is 979175099.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 990571979 - 2⁸ = 990571723 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (990571969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495285989 + 495285990.

It is an arithmetic number, because the mean of its divisors is an integer number (495285990).

Almost surely, 2^990571979 is an apocalyptic number.

990571979 is a deficient number, since it is larger than the sum of its proper divisors (1).

990571979 is an equidigital number, since it uses as much as digits as its factorization.

990571979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1607445, while the sum is 56.

The square root of 990571979 is about 31473.3534755990. The cubic root of 990571979 is about 996.8473978777.

The spelling of 990571979 in words is "nine hundred ninety million, five hundred seventy-one thousand, nine hundred seventy-nine".