20187220 has 12 divisors (see below), whose sum is σ = 42393204. Its totient is φ = 8074880.

The previous prime is 20187203. The next prime is 20187227. The reversal of 20187220 is 2278102.

It can be written as a sum of positive squares in 2 ways, for example, as 5225796 + 14961424 = 2286^2 + 3868^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20187191 and 20187200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20187227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 504661 + ... + 504700.

It is an arithmetic number, because the mean of its divisors is an integer number (3532767).

Almost surely, 2^20187220 is an apocalyptic number.

20187220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20187220 is an abundant number, since it is smaller than the sum of its proper divisors (22205984).

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

20187220 is a wasteful number, since it uses less digits than its factorization.

20187220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1009370 (or 1009368 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 20187220 is about 4493.0190295613. The cubic root of 20187220 is about 272.2861212084.

The spelling of 20187220 in words is "twenty million, one hundred eighty-seven thousand, two hundred twenty".