21259612 has 24 divisors (see below), whose sum is σ = 40989312. Its totient is φ = 9567600.

The previous prime is 21259603. The next prime is 21259627. The reversal of 21259612 is 21695212.

It is a super-2 number, since 2×21259612² = 903942204781088, which contains 22 as substring.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2187 + ... + 6877.

It is an arithmetic number, because the mean of its divisors is an integer number (1707888).

Almost surely, 2^21259612 is an apocalyptic number.

21259612 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21259612 is a deficient number, since it is larger than the sum of its proper divisors (19729700).

21259612 is a wasteful number, since it uses less digits than its factorization.

21259612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4809 (or 4807 counting only the distinct ones).

The product of its digits is 2160, while the sum is 28.

The square root of 21259612 is about 4610.8146785574. The cubic root of 21259612 is about 277.0246690485.

Subtracting 21259612 from its reverse (21695212), we obtain a square (435600 = 660²).

The spelling of 21259612 in words is "twenty-one million, two hundred fifty-nine thousand, six hundred twelve".