99664521 has 16 divisors (see below), whose sum is σ = 145444800. Its totient is φ = 60203520.

The previous prime is 99664517. The next prime is 99664541. The reversal of 99664521 is 12546699.

It is a happy number.

It is not a de Polignac number, because 99664521 - 2² = 99664517 is a prime.

It is not an unprimeable number, because it can be changed into a prime (99664541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5505 + ... + 15153.

It is an arithmetic number, because the mean of its divisors is an integer number (9090300).

Almost surely, 2^99664521 is an apocalyptic number.

It is an amenable number.

99664521 is a deficient number, since it is larger than the sum of its proper divisors (45780279).

99664521 is a wasteful number, since it uses less digits than its factorization.

99664521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9976.

The product of its digits is 116640, while the sum is 42.

The square root of 99664521 is about 9983.2119580824. The cubic root of 99664521 is about 463.6392499803.

The spelling of 99664521 in words is "ninety-nine million, six hundred sixty-four thousand, five hundred twenty-one".