30745721 has 4 divisors (see below), whose sum is σ = 30757200. Its totient is φ = 30734244.

The previous prime is 30745691. The next prime is 30745751. The reversal of 30745721 is 12754703.

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, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (30745691) and next prime (30745751).

It is a cyclic number.

It is not a de Polignac number, because 30745721 - 2⁶ = 30745657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (30745751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 650 + ... + 7868.

It is an arithmetic number, because the mean of its divisors is an integer number (7689300).

Almost surely, 2^30745721 is an apocalyptic number.

It is an amenable number.

30745721 is a deficient number, since it is larger than the sum of its proper divisors (11479).

30745721 is an equidigital number, since it uses as much as digits as its factorization.

30745721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11478.

The product of its (nonzero) digits is 5880, while the sum is 29.

The square root of 30745721 is about 5544.8824153448. The cubic root of 30745721 is about 313.2767951657.

The spelling of 30745721 in words is "thirty million, seven hundred forty-five thousand, seven hundred twenty-one".