31443728 has 20 divisors (see below), whose sum is σ = 61759068. Its totient is φ = 15505920.

The previous prime is 31443721. The next prime is 31443739. The reversal of 31443728 is 82734413.

It can be written as a sum of positive squares in 2 ways, for example, as 26915344 + 4528384 = 5188^2 + 2128^2 .

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 31443694 and 31443703.

It is not an unprimeable number, because it can be changed into a prime (31443721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12293 + ... + 14628.

Almost surely, 2^31443728 is an apocalyptic number.

It is an amenable number.

31443728 is a deficient number, since it is larger than the sum of its proper divisors (30315340).

31443728 is a wasteful number, since it uses less digits than its factorization.

31443728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27002 (or 26996 counting only the distinct ones).

The product of its digits is 16128, while the sum is 32.

The square root of 31443728 is about 5607.4707310872. The cubic root of 31443728 is about 315.6298073705.

The spelling of 31443728 in words is "thirty-one million, four hundred forty-three thousand, seven hundred twenty-eight".