20431908 has 72 divisors (see below), whose sum is σ = 59754240. Its totient is φ = 5765760.

The previous prime is 20431891. The next prime is 20431913. The reversal of 20431908 is 80913402.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21973 + ... + 22883.

It is an arithmetic number, because the mean of its divisors is an integer number (829920).

Almost surely, 2^20431908 is an apocalyptic number.

20431908 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20431908, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29877120).

20431908 is an abundant number, since it is smaller than the sum of its proper divisors (39322332).

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

20431908 is a wasteful number, since it uses less digits than its factorization.

20431908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1017 (or 1012 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 20431908 is about 4520.1668110812. The cubic root of 20431908 is about 273.3818269436.

The spelling of 20431908 in words is "twenty million, four hundred thirty-one thousand, nine hundred eight".