31801980 has 144 divisors (see below), whose sum is σ = 107442720. Its totient is φ = 6999552.

The previous prime is 31801969. The next prime is 31802021. The reversal of 31801980 is 8910813.

It is a super-2 number, since 2×31801980² = 2022731863840800, 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 pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 85074 + ... + 85446.

It is an arithmetic number, because the mean of its divisors is an integer number (746130).

Almost surely, 2^31801980 is an apocalyptic number.

31801980 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 31801980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53721360).

31801980 is an abundant number, since it is smaller than the sum of its proper divisors (75640740).

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

31801980 is a wasteful number, since it uses less digits than its factorization.

31801980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 428 (or 419 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 30.

The square root of 31801980 is about 5639.3244276243. The cubic root of 31801980 is about 316.8239858510.

It can be divided in two parts, 31 and 801980, that added together give a triangular number (802011 = T₁₂₆₆).

The spelling of 31801980 in words is "thirty-one million, eight hundred one thousand, nine hundred eighty".