31989420 has 72 divisors (see below), whose sum is σ = 99315216. Its totient is φ = 8330112.

The previous prime is 31989383. The next prime is 31989439. The reversal of 31989420 is 2498913.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5674 + ... + 9806.

It is an arithmetic number, because the mean of its divisors is an integer number (1379378).

Almost surely, 2^31989420 is an apocalyptic number.

31989420 is a gapful number since it is divisible by the number (30) 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 31989420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49657608).

31989420 is an abundant number, since it is smaller than the sum of its proper divisors (67325796).

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

31989420 is a wasteful number, since it uses less digits than its factorization.

31989420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4191 (or 4186 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 31989420 is about 5655.9190234656. The cubic root of 31989420 is about 317.4452175720.

The spelling of 31989420 in words is "thirty-one million, nine hundred eighty-nine thousand, four hundred twenty".