999989957 has 2 divisors, whose sum is σ = 999989958. Its totient is φ = 999989956.

The previous prime is 999989899. The next prime is 999989981. The reversal of 999989957 is 759989999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 919241761 + 80748196 = 30319^2 + 8986^2 .

It is an emirp because it is prime and its reverse (759989999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999989957 - 2⁸ = 999989701 is a prime.

It is a super-3 number, since 3×999989957³ (a number of 28 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999989257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499994978 + 499994979.

It is an arithmetic number, because the mean of its divisors is an integer number (499994979).

Almost surely, 2^999989957 is an apocalyptic number.

It is an amenable number.

999989957 is a deficient number, since it is larger than the sum of its proper divisors (1).

999989957 is an equidigital number, since it uses as much as digits as its factorization.

999989957 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 999989957 is about 31622.6178075124. The cubic root of 999989957 is about 999.9966523221.

The spelling of 999989957 in words is "nine hundred ninety-nine million, nine hundred eighty-nine thousand, nine hundred fifty-seven".