31621120 has 64 divisors (see below), whose sum is σ = 76282740. Its totient is φ = 12582912.

The previous prime is 31621097. The next prime is 31621123. The reversal of 31621120 is 2112613.

It can be written as a sum of positive squares in 2 ways, for example, as 30294016 + 1327104 = 5504^2 + 1152^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-3 number, since 3×31621120³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a junction number, because it is equal to n+sod(n) for n = 31621094 and 31621103.

It is not an unprimeable number, because it can be changed into a prime (31621123) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163744 + ... + 163936.

Almost surely, 2^31621120 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31621120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38141370).

31621120 is an abundant number, since it is smaller than the sum of its proper divisors (44661620).

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

31621120 is an frugal number, since it uses more digits than its factorization.

31621120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228 (or 200 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 31621120 is about 5623.2659549411. The cubic root of 31621120 is about 316.2222439148. Note that the first 4 decimals are identical.

Adding to 31621120 its reverse (2112613), we get a palindrome (33733733).

The spelling of 31621120 in words is "thirty-one million, six hundred twenty-one thousand, one hundred twenty".