31304728 has 48 divisors (see below), whose sum is σ = 73543680. Its totient is φ = 12382272.

The previous prime is 31304719. The next prime is 31304737. The reversal of 31304728 is 82740313.

It is an interprime number because it is at equal distance from previous prime (31304719) and next prime (31304737).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 31304696 and 31304705.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2025 + ... + 8167.

It is an arithmetic number, because the mean of its divisors is an integer number (1532160).

Almost surely, 2^31304728 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 31304728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36771840).

31304728 is an abundant number, since it is smaller than the sum of its proper divisors (42238952).

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

31304728 is a wasteful number, since it uses less digits than its factorization.

31304728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6176 (or 6165 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 31304728 is about 5595.0628235972. The cubic root of 31304728 is about 315.1640297964.

The spelling of 31304728 in words is "thirty-one million, three hundred four thousand, seven hundred twenty-eight".