30724721 has 2 divisors, whose sum is σ = 30724722. Its totient is φ = 30724720.

The previous prime is 30724709. The next prime is 30724723. The reversal of 30724721 is 12742703.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30250000 + 474721 = 5500^2 + 689^2 .

It is an emirp because it is prime and its reverse (12742703) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30724721 - 2²² = 26530417 is a prime.

Together with 30724723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (30724723) 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 as a sum of consecutive naturals, namely, 15362360 + 15362361.

It is an arithmetic number, because the mean of its divisors is an integer number (15362361).

Almost surely, 2^30724721 is an apocalyptic number.

It is an amenable number.

30724721 is a deficient number, since it is larger than the sum of its proper divisors (1).

30724721 is an equidigital number, since it uses as much as digits as its factorization.

30724721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 30724721 is about 5542.9884538938. The cubic root of 30724721 is about 313.2054539528.

The spelling of 30724721 in words is "thirty million, seven hundred twenty-four thousand, seven hundred twenty-one".