30997840 has 40 divisors (see below), whose sum is σ = 73754208. Its totient is φ = 12109440.

The previous prime is 30997829. The next prime is 30997843. The reversal of 30997840 is 4879903.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 30997793 and 30997802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30997843) 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, 1066 + ... + 7945.

Almost surely, 2^30997840 is an apocalyptic number.

It is an amenable number.

30997840 is an abundant number, since it is smaller than the sum of its proper divisors (42756368).

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

30997840 is a wasteful number, since it uses less digits than its factorization.

30997840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9067 (or 9061 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 30997840 is about 5567.5703857248. The cubic root of 30997840 is about 314.1307689598.

The spelling of 30997840 in words is "thirty million, nine hundred ninety-seven thousand, eight hundred forty".