30887991 has 6 divisors (see below), whose sum is σ = 44616000. Its totient is φ = 20591988.

The previous prime is 30887981. The next prime is 30887999. The reversal of 30887991 is 19978803.

It is not a de Polignac number, because 30887991 - 2⁵ = 30887959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30887999) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1715991 + ... + 1716008.

It is an arithmetic number, because the mean of its divisors is an integer number (7436000).

Almost surely, 2^30887991 is an apocalyptic number.

30887991 is a deficient number, since it is larger than the sum of its proper divisors (13728009).

30887991 is a wasteful number, since it uses less digits than its factorization.

30887991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3432005 (or 3432002 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 30887991 is about 5557.6965552286. The cubic root of 30887991 is about 313.7592614315.

It can be divided in two parts, 30887 and 991, that added together give a triangular number (31878 = T₂₅₂).

The spelling of 30887991 in words is "thirty million, eight hundred eighty-seven thousand, nine hundred ninety-one".