21599090 has 32 divisors (see below), whose sum is σ = 40170816. Its totient is φ = 8357440.

The previous prime is 21599089. The next prime is 21599099. The reversal of 21599090 is 9099512.

It is a self number, because there is not a number n which added to its sum of digits gives 21599090.

It is not an unprimeable number, because it can be changed into a prime (21599099) 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, 43745 + ... + 44235.

It is an arithmetic number, because the mean of its divisors is an integer number (1255338).

Almost surely, 2^21599090 is an apocalyptic number.

21599090 is a deficient number, since it is larger than the sum of its proper divisors (18571726).

21599090 is a wasteful number, since it uses less digits than its factorization.

21599090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 634.

The product of its (nonzero) digits is 7290, while the sum is 35.

The square root of 21599090 is about 4647.4821140054. The cubic root of 21599090 is about 278.4914189935.

The spelling of 21599090 in words is "twenty-one million, five hundred ninety-nine thousand, ninety".