31643664 has 160 divisors (see below), whose sum is σ = 98743680. Its totient is φ = 8626176.

The previous prime is 31643663. The next prime is 31643671. The reversal of 31643664 is 46634613.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31643663) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 201474 + ... + 201630.

It is an arithmetic number, because the mean of its divisors is an integer number (617148).

Almost surely, 2^31643664 is an apocalyptic number.

31643664 is a gapful number since it is divisible by the number (34) 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 31643664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49371840).

31643664 is an abundant number, since it is smaller than the sum of its proper divisors (67100016).

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

31643664 is a wasteful number, since it uses less digits than its factorization.

31643664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217 (or 211 counting only the distinct ones).

The product of its digits is 31104, while the sum is 33.

The square root of 31643664 is about 5625.2701268472. The cubic root of 31643664 is about 316.2973753541.

The spelling of 31643664 in words is "thirty-one million, six hundred forty-three thousand, six hundred sixty-four".