31120020 has 72 divisors (see below), whose sum is σ = 95580576. Its totient is φ = 8194752.

The previous prime is 31120009. The next prime is 31120027. The reversal of 31120020 is 2002113.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 31119984 and 31120011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31120027) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13899 + ... + 15981.

It is an arithmetic number, because the mean of its divisors is an integer number (1327508).

Almost surely, 2^31120020 is an apocalyptic number.

31120020 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 31120020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47790288).

31120020 is an abundant number, since it is smaller than the sum of its proper divisors (64460556).

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

31120020 is a wasteful number, since it uses less digits than its factorization.

31120020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2181 (or 2176 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 31120020 is about 5578.5320649791. The cubic root of 31120020 is about 314.5429501642.

Adding to 31120020 its reverse (2002113), we get a palindrome (33122133).

The spelling of 31120020 in words is "thirty-one million, one hundred twenty thousand, twenty".