21702065 has 16 divisors (see below), whose sum is σ = 32469120. Its totient is φ = 13528320.

The previous prime is 21702059. The next prime is 21702067. The reversal of 21702065 is 56020712.

It is not a de Polignac number, because 21702065 - 2⁴ = 21702049 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21702065.

It is not an unprimeable number, because it can be changed into a prime (21702067) 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, 27800 + ... + 28569.

It is an arithmetic number, because the mean of its divisors is an integer number (2029320).

Almost surely, 2^21702065 is an apocalyptic number.

It is an amenable number.

21702065 is a deficient number, since it is larger than the sum of its proper divisors (10767055).

21702065 is a wasteful number, since it uses less digits than its factorization.

21702065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56392.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21702065 is about 4658.5475204188. The cubic root of 21702065 is about 278.9332925482.

Adding to 21702065 its reverse (56020712), we get a palindrome (77722777).

The spelling of 21702065 in words is "twenty-one million, seven hundred two thousand, sixty-five".