22815220 has 24 divisors (see below), whose sum is σ = 48700008. Its totient is φ = 8976000.

The previous prime is 22815217. The next prime is 22815227. The reversal of 22815220 is 2251822.

It can be written as a sum of positive squares in 4 ways, for example, as 574564 + 22240656 = 758^2 + 4716^2 .

It is a junction number, because it is equal to n+sod(n) for n = 22815191 and 22815200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22815227) 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, 8131 + ... + 10570.

It is an arithmetic number, because the mean of its divisors is an integer number (2029167).

Almost surely, 2^22815220 is an apocalyptic number.

22815220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

22815220 is an abundant number, since it is smaller than the sum of its proper divisors (25884788).

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

22815220 is a wasteful number, since it uses less digits than its factorization.

22815220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18771 (or 18769 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 22815220 is about 4776.5280277624. The cubic root of 22815220 is about 283.6230700118.

The spelling of 22815220 in words is "twenty-two million, eight hundred fifteen thousand, two hundred twenty".