20151565 has 16 divisors (see below), whose sum is σ = 28839168. Its totient is φ = 13216896.

The previous prime is 20151539. The next prime is 20151587. The reversal of 20151565 is 56515102.

It is not a de Polignac number, because 20151565 - 2¹¹ = 20149517 is a prime.

It is a Duffinian number.

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, 11712 + ... + 13321.

It is an arithmetic number, because the mean of its divisors is an integer number (1802448).

Almost surely, 2^20151565 is an apocalyptic number.

It is an amenable number.

20151565 is a deficient number, since it is larger than the sum of its proper divisors (8687603).

20151565 is a wasteful number, since it uses less digits than its factorization.

20151565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25068.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 20151565 is about 4489.0494539490. The cubic root of 20151565 is about 272.1257213291.

Adding to 20151565 its reverse (56515102), we get a palindrome (76666667).

The spelling of 20151565 in words is "twenty million, one hundred fifty-one thousand, five hundred sixty-five".