21599091 has 12 divisors (see below), whose sum is σ = 31239000. Its totient is φ = 14380800.

The previous prime is 21599089. The next prime is 21599099. The reversal of 21599091 is 19099512.

It is not a de Polignac number, because 21599091 - 2¹ = 21599089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21599099) 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 11 ways as a sum of consecutive naturals, for example, 12691 + ... + 14291.

It is an arithmetic number, because the mean of its divisors is an integer number (2603250).

Almost surely, 2^21599091 is an apocalyptic number.

21599091 is a deficient number, since it is larger than the sum of its proper divisors (9639909).

21599091 is a wasteful number, since it uses less digits than its factorization.

21599091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3106 (or 3103 counting only the distinct ones).

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

The square root of 21599091 is about 4647.4822215905. The cubic root of 21599091 is about 278.4914232914.

The spelling of 21599091 in words is "twenty-one million, five hundred ninety-nine thousand, ninety-one".