31321020 has 24 divisors (see below), whose sum is σ = 87699024. Its totient is φ = 8352256.

The previous prime is 31321013. The next prime is 31321033. The reversal of 31321020 is 2012313.

It is a happy number.

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 = 31320987 and 31321005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 260949 + ... + 261068.

It is an arithmetic number, because the mean of its divisors is an integer number (3654126).

Almost surely, 2^31321020 is an apocalyptic number.

31321020 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31321020 is an abundant number, since it is smaller than the sum of its proper divisors (56378004).

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

31321020 is a wasteful number, since it uses less digits than its factorization.

31321020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522029 (or 522027 counting only the distinct ones).

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

The square root of 31321020 is about 5596.5185606768. The cubic root of 31321020 is about 315.2186941896.

Adding to 31321020 its reverse (2012313), we get a palindrome (33333333).

The spelling of 31321020 in words is "thirty-one million, three hundred twenty-one thousand, twenty".