31489920 has 384 divisors, whose sum is σ = 137479680. Its totient is φ = 6451200.

The previous prime is 31489919. The next prime is 31489943. The reversal of 31489920 is 2998413.

It is a tau number, because it is divible by the number of its divisors (384).

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

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 443485 + ... + 443555.

It is an arithmetic number, because the mean of its divisors is an integer number (358020).

Almost surely, 2^31489920 is an apocalyptic number.

31489920 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 31489920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68739840).

31489920 is an abundant number, since it is smaller than the sum of its proper divisors (105989760).

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

31489920 is a wasteful number, since it uses less digits than its factorization.

31489920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114 (or 99 counting only the distinct ones).

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

The square root of 31489920 is about 5611.5880105368. The cubic root of 31489920 is about 315.7842890377.

The spelling of 31489920 in words is "thirty-one million, four hundred eighty-nine thousand, nine hundred twenty".