21500086 has 24 divisors (see below), whose sum is σ = 34012440. Its totient is φ = 10186176.

The previous prime is 21500069. The next prime is 21500111. The reversal of 21500086 is 68000512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 241530 + ... + 241618.

It is an arithmetic number, because the mean of its divisors is an integer number (1417185).

Almost surely, 2^21500086 is an apocalyptic number.

21500086 is a deficient number, since it is larger than the sum of its proper divisors (12512354).

21500086 is an equidigital number, since it uses as much as digits as its factorization.

21500086 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 187 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 21500086 is about 4636.8185213571. The cubic root of 21500086 is about 278.0652590788.

Adding to 21500086 its reverse (68000512), we get a palindrome (89500598).

It can be divided in two parts, 215000 and 86, that multiplied together give a square (18490000 = 4300²).

The spelling of 21500086 in words is "twenty-one million, five hundred thousand, eighty-six".