99649721 has 6 divisors (see below), whose sum is σ = 102145722. Its totient is φ = 97156880.

The previous prime is 99649679. The next prime is 99649727. The reversal of 99649721 is 12794699.

It can be written as a sum of positive squares in only one way, i.e., 60762025 + 38887696 = 7795^2 + 6236^2 .

It is not a de Polignac number, because 99649721 - 2⁶ = 99649657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99649727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 63140 + ... + 64698.

It is an arithmetic number, because the mean of its divisors is an integer number (17024287).

Almost surely, 2^99649721 is an apocalyptic number.

It is an amenable number.

99649721 is a deficient number, since it is larger than the sum of its proper divisors (2496001).

99649721 is an frugal number, since it uses more digits than its factorization.

99649721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3159 (or 1600 counting only the distinct ones).

The product of its digits is 244944, while the sum is 47.

The square root of 99649721 is about 9982.4706861578. The cubic root of 99649721 is about 463.6162989826.

The spelling of 99649721 in words is "ninety-nine million, six hundred forty-nine thousand, seven hundred twenty-one".