21088065 has 16 divisors (see below), whose sum is σ = 34217856. Its totient is φ = 11088000.

The previous prime is 21088061. The next prime is 21088069. The reversal of 21088065 is 56088012.

It is an interprime number because it is at equal distance from previous prime (21088061) and next prime (21088069).

It is not a de Polignac number, because 21088065 - 2² = 21088061 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21088061) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8836 + ... + 10965.

It is an arithmetic number, because the mean of its divisors is an integer number (2138616).

Almost surely, 2^21088065 is an apocalyptic number.

It is an amenable number.

21088065 is a deficient number, since it is larger than the sum of its proper divisors (13129791).

21088065 is a wasteful number, since it uses less digits than its factorization.

21088065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19880.

The product of its (nonzero) digits is 3840, while the sum is 30.

The square root of 21088065 is about 4592.1743216041. The cubic root of 21088065 is about 276.2775379822.

The spelling of 21088065 in words is "twenty-one million, eighty-eight thousand, sixty-five".