21265740 has 60 divisors (see below), whose sum is σ = 66716496. Its totient is φ = 5670432.

The previous prime is 21265709. The next prime is 21265747. The reversal of 21265740 is 4756212.

21265740 is a `hidden beast` number, since 2 + 1 + 2 + 657 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21265747) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4944 + ... + 8183.

Almost surely, 2^21265740 is an apocalyptic number.

21265740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21265740 is an abundant number, since it is smaller than the sum of its proper divisors (45450756).

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

21265740 is a wasteful number, since it uses less digits than its factorization.

21265740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13148 (or 13137 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 21265740 is about 4611.4791553253. The cubic root of 21265740 is about 277.0512835839.

The spelling of 21265740 in words is "twenty-one million, two hundred sixty-five thousand, seven hundred forty".