99977989 has 2 divisors, whose sum is σ = 99977990. Its totient is φ = 99977988.

The previous prime is 99977923. The next prime is 99978001. The reversal of 99977989 is 98977999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72760900 + 27217089 = 8530^2 + 5217^2 .

It is a cyclic number.

It is not a de Polignac number, because 99977989 - 2⁷ = 99977861 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99977909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49988994 + 49988995.

It is an arithmetic number, because the mean of its divisors is an integer number (49988995).

Almost surely, 2^99977989 is an apocalyptic number.

It is an amenable number.

99977989 is a deficient number, since it is larger than the sum of its proper divisors (1).

99977989 is an equidigital number, since it uses as much as digits as its factorization.

99977989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23147208, while the sum is 67.

The square root of 99977989 is about 9998.8993894328. The cubic root of 99977989 is about 464.1248255251.

The spelling of 99977989 in words is "ninety-nine million, nine hundred seventy-seven thousand, nine hundred eighty-nine".