20215530 has 24 divisors (see below), whose sum is σ = 52560612. Its totient is φ = 5390784.

The previous prime is 20215529. The next prime is 20215537. The reversal of 20215530 is 3551202.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19421649 + 793881 = 4407^2 + 891^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (20215537) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 112219 + ... + 112398.

Almost surely, 2^20215530 is an apocalyptic number.

20215530 is an abundant number, since it is smaller than the sum of its proper divisors (32345082).

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

20215530 is a wasteful number, since it uses less digits than its factorization.

20215530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224630 (or 224627 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 20215530 is about 4496.1683687335. The cubic root of 20215530 is about 272.4133439354.

Adding to 20215530 its reverse (3551202), we get a palindrome (23766732).

The spelling of 20215530 in words is "twenty million, two hundred fifteen thousand, five hundred thirty".