31724138 has 4 divisors (see below), whose sum is σ = 47586210. Its totient is φ = 15862068.

The previous prime is 31724137. The next prime is 31724171. The reversal of 31724138 is 83142713.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 31663129 + 61009 = 5627^2 + 247^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 31724138.

It is not an unprimeable number, because it can be changed into a prime (31724137) 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 as a sum of consecutive naturals, namely, 7931033 + ... + 7931036.

Almost surely, 2^31724138 is an apocalyptic number.

31724138 is a deficient number, since it is larger than the sum of its proper divisors (15862072).

31724138 is a wasteful number, since it uses less digits than its factorization.

31724138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15862071.

The product of its digits is 4032, while the sum is 29.

The square root of 31724138 is about 5632.4184858727. The cubic root of 31724138 is about 316.5652769898.

The spelling of 31724138 in words is "thirty-one million, seven hundred twenty-four thousand, one hundred thirty-eight".