30651981 has 4 divisors (see below), whose sum is σ = 40869312. Its totient is φ = 20434652.

The previous prime is 30651977. The next prime is 30652007. The reversal of 30651981 is 18915603.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 30651981 - 2² = 30651977 is a prime.

It is a super-2 number, since 2×30651981² = 1879087878448722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30651931) 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, 5108661 + ... + 5108666.

It is an arithmetic number, because the mean of its divisors is an integer number (10217328).

Almost surely, 2^30651981 is an apocalyptic number.

It is an amenable number.

30651981 is a deficient number, since it is larger than the sum of its proper divisors (10217331).

30651981 is a wasteful number, since it uses less digits than its factorization.

30651981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10217330.

The product of its (nonzero) digits is 6480, while the sum is 33.

The square root of 30651981 is about 5536.4231232810. The cubic root of 30651981 is about 312.9580899766.

The spelling of 30651981 in words is "thirty million, six hundred fifty-one thousand, nine hundred eighty-one".