31640000 has 140 divisors (see below), whose sum is σ = 90458544. Its totient is φ = 10752000.

The previous prime is 31639999. The next prime is 31640003. The reversal of 31640000 is 4613.

It is a tau number, because it is divible by the number of its divisors (140).

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31640003) 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 19 ways as a sum of consecutive naturals, for example, 279944 + ... + 280056.

Almost surely, 2^31640000 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 31640000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45229272).

31640000 is an abundant number, since it is smaller than the sum of its proper divisors (58818544).

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

31640000 is an equidigital number, since it uses as much as digits as its factorization.

31640000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 31640000 is about 5624.9444441701. The cubic root of 31640000 is about 316.2851669247.

Adding to 31640000 its reverse (4613), we get a palindrome (31644613).

The spelling of 31640000 in words is "thirty-one million, six hundred forty thousand".