31121664 has 108 divisors (see below), whose sum is σ = 96468624. Its totient is φ = 8881152.

The previous prime is 31121663. The next prime is 31121687. The reversal of 31121664 is 46612113.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (31121663) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37219 + ... + 38045.

It is an arithmetic number, because the mean of its divisors is an integer number (893228).

Almost surely, 2^31121664 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 31121664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48234312).

31121664 is an abundant number, since it is smaller than the sum of its proper divisors (65346960).

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

31121664 is an equidigital number, since it uses as much as digits as its factorization.

31121664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 860 (or 839 counting only the distinct ones).

The product of its digits is 864, while the sum is 24.

The square root of 31121664 is about 5578.6794136247. The cubic root of 31121664 is about 314.5484889300.

Adding to 31121664 its reverse (46612113), we get a palindrome (77733777).

The spelling of 31121664 in words is "thirty-one million, one hundred twenty-one thousand, six hundred sixty-four".