99820521 has 6 divisors (see below), whose sum is σ = 144185210. Its totient is φ = 66547008.

The previous prime is 99820519. The next prime is 99820541. The reversal of 99820521 is 12502899.

It can be written as a sum of positive squares in only one way, i.e., 59675625 + 40144896 = 7725^2 + 6336^2 .

It is not a de Polignac number, because 99820521 - 2¹ = 99820519 is a prime.

It is a super-2 number, since 2×99820521² = 19928272825422882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99820541) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5545576 + ... + 5545593.

Almost surely, 2^99820521 is an apocalyptic number.

It is an amenable number.

99820521 is a deficient number, since it is larger than the sum of its proper divisors (44364689).

99820521 is a wasteful number, since it uses less digits than its factorization.

99820521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11091175 (or 11091172 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 99820521 is about 9991.0220197936. The cubic root of 99820521 is about 463.8810278234.

The spelling of 99820521 in words is "ninety-nine million, eight hundred twenty thousand, five hundred twenty-one".