989979923 has 2 divisors, whose sum is σ = 989979924. Its totient is φ = 989979922.

The previous prime is 989979911. The next prime is 989979929. The reversal of 989979923 is 329979989.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 989979923 - 2¹² = 989975827 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 989979923.

It is not a weakly prime, because it can be changed into another prime (989979929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494989961 + 494989962.

It is an arithmetic number, because the mean of its divisors is an integer number (494989962).

Almost surely, 2^989979923 is an apocalyptic number.

989979923 is a deficient number, since it is larger than the sum of its proper divisors (1).

989979923 is an equidigital number, since it uses as much as digits as its factorization.

989979923 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19840464, while the sum is 65.

The square root of 989979923 is about 31463.9463990136. The cubic root of 989979923 is about 996.6487560430.

The spelling of 989979923 in words is "nine hundred eighty-nine million, nine hundred seventy-nine thousand, nine hundred twenty-three".