20091920 has 20 divisors (see below), whose sum is σ = 46713900. Its totient is φ = 8036736.

The previous prime is 20091913. The next prime is 20091923. The reversal of 20091920 is 2919002.

It can be written as a sum of positive squares in 2 ways, for example, as 12845056 + 7246864 = 3584^2 + 2692^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (20091923) 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, 125495 + ... + 125654.

It is an arithmetic number, because the mean of its divisors is an integer number (2335695).

Almost surely, 2^20091920 is an apocalyptic number.

20091920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20091920 is an abundant number, since it is smaller than the sum of its proper divisors (26621980).

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

20091920 is a wasteful number, since it uses less digits than its factorization.

20091920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251162 (or 251156 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 20091920 is about 4482.4011422451. The cubic root of 20091920 is about 271.8569749797.

The spelling of 20091920 in words is "twenty million, ninety-one thousand, nine hundred twenty".