31720432 has 40 divisors (see below), whose sum is σ = 64170000. Its totient is φ = 15171072.

The previous prime is 31720421. The next prime is 31720439. The reversal of 31720432 is 23402713.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31720439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63319 + ... + 63817.

It is an arithmetic number, because the mean of its divisors is an integer number (1604250).

Almost surely, 2^31720432 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 31720432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32085000).

31720432 is an abundant number, since it is smaller than the sum of its proper divisors (32449568).

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

31720432 is a wasteful number, since it uses less digits than its factorization.

31720432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 673 (or 667 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 31720432 is about 5632.0894879254. The cubic root of 31720432 is about 316.5529495038.

Subtracting from 31720432 its product of nonzero digits (1008), we obtain a square (31719424 = 5632²).

The spelling of 31720432 in words is "thirty-one million, seven hundred twenty thousand, four hundred thirty-two".