99720657 has 12 divisors (see below), whose sum is σ = 152514180. Its totient is φ = 62569728.

The previous prime is 99720653. The next prime is 99720667. The reversal of 99720657 is 75602799.

It can be written as a sum of positive squares in 2 ways, for example, as 79281216 + 20439441 = 8904^2 + 4521^2 .

It is not a de Polignac number, because 99720657 - 2² = 99720653 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (99720653) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 325732 + ... + 326037.

It is an arithmetic number, because the mean of its divisors is an integer number (12709515).

Almost surely, 2^99720657 is an apocalyptic number.

It is an amenable number.

99720657 is a deficient number, since it is larger than the sum of its proper divisors (52793523).

99720657 is a wasteful number, since it uses less digits than its factorization.

99720657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 651792 (or 651789 counting only the distinct ones).

The product of its (nonzero) digits is 238140, while the sum is 45.

The square root of 99720657 is about 9986.0230822886. The cubic root of 99720657 is about 463.7262818470.

The spelling of 99720657 in words is "ninety-nine million, seven hundred twenty thousand, six hundred fifty-seven".