30721601 has 4 divisors (see below), whose sum is σ = 32528772. Its totient is φ = 28914432.

The previous prime is 30721573. The next prime is 30721619. The reversal of 30721601 is 10612703.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10612703 = 131 ⋅81013.

It can be written as a sum of positive squares in 2 ways, for example, as 21715600 + 9006001 = 4660^2 + 3001^2 .

It is a cyclic number.

It is not a de Polignac number, because 30721601 - 2¹⁰ = 30720577 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (30721001) 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, 903560 + ... + 903593.

It is an arithmetic number, because the mean of its divisors is an integer number (8132193).

Almost surely, 2^30721601 is an apocalyptic number.

It is an amenable number.

30721601 is a deficient number, since it is larger than the sum of its proper divisors (1807171).

30721601 is a wasteful number, since it uses less digits than its factorization.

30721601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1807170.

The product of its (nonzero) digits is 252, while the sum is 20.

The square root of 30721601 is about 5542.7070101170. The cubic root of 30721601 is about 313.1948519135.

The spelling of 30721601 in words is "thirty million, seven hundred twenty-one thousand, six hundred one".