30991488 has 192 divisors, whose sum is σ = 97675200. Its totient is φ = 8673280.

The previous prime is 30991481. The next prime is 30991501. The reversal of 30991488 is 88419903.

It is a Cunningham number, because it is equal to 5567²-1.

It is a tau number, because it is divible by the number of its divisors (192).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30991481) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1068658 + ... + 1068686.

It is an arithmetic number, because the mean of its divisors is an integer number (508725).

Almost surely, 2^30991488 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 30991488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48837600).

30991488 is an abundant number, since it is smaller than the sum of its proper divisors (66683712).

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

30991488 is a wasteful number, since it uses less digits than its factorization.

30991488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 68 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 42.

The square root of 30991488 is about 5566.9999101850. Note that the first 4 decimals coincide. The cubic root of 30991488 is about 314.1093105296.

The spelling of 30991488 in words is "thirty million, nine hundred ninety-one thousand, four hundred eighty-eight".