989999957 has 2 divisors, whose sum is σ = 989999958. Its totient is φ = 989999956.

The previous prime is 989999951. The next prime is 989999993. The reversal of 989999957 is 759999989.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 939177316 + 50822641 = 30646^2 + 7129^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-989999957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989999951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494999978 + 494999979.

It is an arithmetic number, because the mean of its divisors is an integer number (494999979).

Almost surely, 2^989999957 is an apocalyptic number.

It is an amenable number.

989999957 is a deficient number, since it is larger than the sum of its proper divisors (1).

989999957 is an equidigital number, since it uses as much as digits as its factorization.

989999957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 148803480, while the sum is 74.

The square root of 989999957 is about 31464.2647617897. The cubic root of 989999957 is about 996.6554789829.

The spelling of 989999957 in words is "nine hundred eighty-nine million, nine hundred ninety-nine thousand, nine hundred fifty-seven".