21265500 has 48 divisors (see below), whose sum is σ = 61929504. Its totient is φ = 5670400.

The previous prime is 21265459. The next prime is 21265523. The reversal of 21265500 is 556212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5589 + ... + 8588.

It is an arithmetic number, because the mean of its divisors is an integer number (1290198).

Almost surely, 2^21265500 is an apocalyptic number.

21265500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21265500 is an abundant number, since it is smaller than the sum of its proper divisors (40664004).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21265500 is a wasteful number, since it uses less digits than its factorization.

21265500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14199 (or 14187 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 21265500 is about 4611.4531332325. The cubic root of 21265500 is about 277.0502413354.

It can be divided in two parts, 2126 and 5500, that added together give a triangular number (7626 = T₁₂₃).

The spelling of 21265500 in words is "twenty-one million, two hundred sixty-five thousand, five hundred".