30642721 has 4 divisors (see below), whose sum is σ = 32445252. Its totient is φ = 28840192.

The previous prime is 30642713. The next prime is 30642737. The reversal of 30642721 is 12724603.

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 12673600 + 17969121 = 3560^2 + 4239^2 .

It is a cyclic number.

It is not a de Polignac number, because 30642721 - 2³ = 30642713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (30642701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 901240 + ... + 901273.

It is an arithmetic number, because the mean of its divisors is an integer number (8111313).

Almost surely, 2^30642721 is an apocalyptic number.

It is an amenable number.

30642721 is a deficient number, since it is larger than the sum of its proper divisors (1802531).

30642721 is a wasteful number, since it uses less digits than its factorization.

30642721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1802530.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 30642721 is about 5535.5867800984. The cubic root of 30642721 is about 312.9265717985.

The spelling of 30642721 in words is "thirty million, six hundred forty-two thousand, seven hundred twenty-one".