31231020 has 48 divisors (see below), whose sum is σ = 87867360. Its totient is φ = 8288256.

The previous prime is 31231009. The next prime is 31231027. The reversal of 31231020 is 2013213.

It is a happy number.

It is a super-2 number, since 2×31231020² = 1950753220480800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 31230987 and 31231005.

It is not an unprimeable number, because it can be changed into a prime (31231027) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12604 + ... + 14876.

It is an arithmetic number, because the mean of its divisors is an integer number (1830570).

Almost surely, 2^31231020 is an apocalyptic number.

31231020 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31231020 is an abundant number, since it is smaller than the sum of its proper divisors (56636340).

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

31231020 is a wasteful number, since it uses less digits than its factorization.

31231020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2514 (or 2512 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 31231020 is about 5588.4720630956. The cubic root of 31231020 is about 314.9164807551.

Adding to 31231020 its reverse (2013213), we get a palindrome (33244233).

The spelling of 31231020 in words is "thirty-one million, two hundred thirty-one thousand, twenty".