30981440 has 56 divisors (see below), whose sum is σ = 84319872. Its totient is φ = 10621440.

The previous prime is 30981427. The next prime is 30981443. The reversal of 30981440 is 4418903.

It is a tau number, because it is divible by the number of its divisors (56).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30981443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4676 + ... + 9155.

It is an arithmetic number, because the mean of its divisors is an integer number (1505712).

Almost surely, 2^30981440 is an apocalyptic number.

It is an amenable number.

30981440 is an abundant number, since it is smaller than the sum of its proper divisors (53338432).

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

30981440 is a wasteful number, since it uses less digits than its factorization.

30981440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13855 (or 13845 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 30981440 is about 5566.0973760796. The cubic root of 30981440 is about 314.0753602235.

The spelling of 30981440 in words is "thirty million, nine hundred eighty-one thousand, four hundred forty".