31309992 has 192 divisors, whose sum is σ = 105281280. Its totient is φ = 8211456.

The previous prime is 31309987. The next prime is 31310003. The reversal of 31309992 is 29990313.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 428868 + ... + 428940.

It is an arithmetic number, because the mean of its divisors is an integer number (548340).

Almost surely, 2^31309992 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 31309992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52640640).

31309992 is an abundant number, since it is smaller than the sum of its proper divisors (73971288).

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

31309992 is a wasteful number, since it uses less digits than its factorization.

31309992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152 (or 145 counting only the distinct ones).

The product of its (nonzero) digits is 13122, while the sum is 36.

The square root of 31309992 is about 5595.5332185592. The cubic root of 31309992 is about 315.1816941193.

The spelling of 31309992 in words is "thirty-one million, three hundred nine thousand, nine hundred ninety-two".