20215312 has 40 divisors (see below), whose sum is σ = 44669016. Its totient is φ = 8779776.

The previous prime is 20215303. The next prime is 20215319. The reversal of 20215312 is 21351202.

It can be written as a sum of positive squares in 4 ways, for example, as 2876416 + 17338896 = 1696^2 + 4164^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20215319) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 678 + ... + 6394.

Almost surely, 2^20215312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20215312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22334508).

20215312 is an abundant number, since it is smaller than the sum of its proper divisors (24453704).

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

20215312 is a wasteful number, since it uses less digits than its factorization.

20215312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5755 (or 5749 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 20215312 is about 4496.1441258038. The cubic root of 20215312 is about 272.4123647160.

Adding to 20215312 its reverse (21351202), we get a palindrome (41566514).

The spelling of 20215312 in words is "twenty million, two hundred fifteen thousand, three hundred twelve".