99977721 has 16 divisors (see below), whose sum is σ = 136963008. Its totient is φ = 64832000.

The previous prime is 99977707. The next prime is 99977729. The reversal of 99977721 is 12777999.

It is a cyclic number.

It is not a de Polignac number, because 99977721 - 2⁷ = 99977593 is a prime.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (99977729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48310 + ... + 50336.

It is an arithmetic number, because the mean of its divisors is an integer number (8560188).

Almost surely, 2^99977721 is an apocalyptic number.

It is an amenable number.

99977721 is a deficient number, since it is larger than the sum of its proper divisors (36985287).

99977721 is a wasteful number, since it uses less digits than its factorization.

99977721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2472.

The product of its digits is 500094, while the sum is 51.

The square root of 99977721 is about 9998.8859879489. The cubic root of 99977721 is about 464.1244108152.

The spelling of 99977721 in words is "ninety-nine million, nine hundred seventy-seven thousand, seven hundred twenty-one".