30991992 has 64 divisors (see below), whose sum is σ = 80784000. Its totient is φ = 9899904.

The previous prime is 30991991. The next prime is 30991993. The reversal of 30991992 is 29919903.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (30991991) and next prime (30991993).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30991991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60634 + ... + 61142.

It is an arithmetic number, because the mean of its divisors is an integer number (1262250).

Almost surely, 2^30991992 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 30991992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40392000).

30991992 is an abundant number, since it is smaller than the sum of its proper divisors (49792008).

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

30991992 is a wasteful number, since it uses less digits than its factorization.

30991992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 620 (or 616 counting only the distinct ones).

The product of its (nonzero) digits is 39366, while the sum is 42.

The square root of 30991992 is about 5567.0451767522. The cubic root of 30991992 is about 314.1110132577. Note that the first 3 decimals are identical.

The spelling of 30991992 in words is "thirty million, nine hundred ninety-one thousand, nine hundred ninety-two".