31129428 has 48 divisors (see below), whose sum is σ = 79934400. Its totient is φ = 9428320.

The previous prime is 31129411. The next prime is 31129433. The reversal of 31129428 is 82492113.

It is a hoax number, since the sum of its digits (30) 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 = 31129395 and 31129404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14998 + ... + 16946.

It is an arithmetic number, because the mean of its divisors is an integer number (1665300).

Almost surely, 2^31129428 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 31129428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39967200).

31129428 is an abundant number, since it is smaller than the sum of its proper divisors (48804972).

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

31129428 is a wasteful number, since it uses less digits than its factorization.

31129428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1989 (or 1965 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The square root of 31129428 is about 5579.3752338412. The cubic root of 31129428 is about 314.5746438233.

The spelling of 31129428 in words is "thirty-one million, one hundred twenty-nine thousand, four hundred twenty-eight".