30512981 has 4 divisors (see below), whose sum is σ = 30644172. Its totient is φ = 30381792.

The previous prime is 30512969. The next prime is 30512983. The reversal of 30512981 is 18921503.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4553956 + 25959025 = 2134^2 + 5095^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-30512981 is a prime.

It is a super-2 number, since 2×30512981² = 1862084019012722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30512983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65246 + ... + 65711.

It is an arithmetic number, because the mean of its divisors is an integer number (7661043).

Almost surely, 2^30512981 is an apocalyptic number.

It is an amenable number.

30512981 is a deficient number, since it is larger than the sum of its proper divisors (131191).

30512981 is a wasteful number, since it uses less digits than its factorization.

30512981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131190.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 30512981 is about 5523.8556280917. The cubic root of 30512981 is about 312.4843076920.

The spelling of 30512981 in words is "thirty million, five hundred twelve thousand, nine hundred eighty-one".