31159920 has 240 divisors, whose sum is σ = 112805280. Its totient is φ = 7096320.

The previous prime is 31159903. The next prime is 31159951. The reversal of 31159920 is 2995113.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×31159920² = 1941881228812800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

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, 842142 + ... + 842178.

It is an arithmetic number, because the mean of its divisors is an integer number (470022).

Almost surely, 2^31159920 is an apocalyptic number.

31159920 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 31159920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (56402640).

31159920 is an abundant number, since it is smaller than the sum of its proper divisors (81645360).

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

31159920 is a wasteful number, since it uses less digits than its factorization.

31159920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 2430, while the sum is 30.

The square root of 31159920 is about 5582.1071290329. The cubic root of 31159920 is about 314.6773213699.

It can be divided in two parts, 31 and 159920, that added together give a palindrome (159951).

The spelling of 31159920 in words is "thirty-one million, one hundred fifty-nine thousand, nine hundred twenty".