21465081 has 20 divisors (see below), whose sum is σ = 34981584. Its totient is φ = 13008600.

The previous prime is 21465071. The next prime is 21465121. The reversal of 21465081 is 18056412.

21465081 is a `hidden beast` number, since 2 + 1 + 4 + 650 + 8 + 1 = 666.

It is not a de Polignac number, because 21465081 - 2⁷ = 21464953 is a prime.

It is a super-2 number, since 2×21465081² = 921499404673122, which contains 22 as substring.

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 (21465061) 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, 11155 + ... + 12936.

Almost surely, 2^21465081 is an apocalyptic number.

It is an amenable number.

21465081 is a deficient number, since it is larger than the sum of its proper divisors (13516503).

21465081 is a wasteful number, since it uses less digits than its factorization.

21465081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24114 (or 24105 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 21465081 is about 4633.0423050087. The cubic root of 21465081 is about 277.9142680277.

It can be divided in two parts, 2146 and 5081, that added together give a palindrome (7227).

The spelling of 21465081 in words is "twenty-one million, four hundred sixty-five thousand, eighty-one".