99901521 has 12 divisors (see below), whose sum is σ = 145924740. Its totient is φ = 65852160.

The previous prime is 99901507. The next prime is 99901541. The reversal of 99901521 is 12510999.

It can be written as a sum of positive squares in 2 ways, for example, as 7049025 + 92852496 = 2655^2 + 9636^2 .

It is not a de Polignac number, because 99901521 - 2¹³ = 99893329 is a prime.

It is a super-2 number, since 2×99901521² = 19960627796226882, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (99901541) 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, 61560 + ... + 63161.

It is an arithmetic number, because the mean of its divisors is an integer number (12160395).

Almost surely, 2^99901521 is an apocalyptic number.

It is an amenable number.

99901521 is a deficient number, since it is larger than the sum of its proper divisors (46023219).

99901521 is a wasteful number, since it uses less digits than its factorization.

99901521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124816 (or 124813 counting only the distinct ones).

The product of its (nonzero) digits is 7290, while the sum is 36.

The square root of 99901521 is about 9995.0748371385. The cubic root of 99901521 is about 464.0064669754.

It can be divided in two parts, 9990 and 1521, that added together give a palindrome (11511).

The spelling of 99901521 in words is "ninety-nine million, nine hundred one thousand, five hundred twenty-one".