30721573 has 2 divisors, whose sum is σ = 30721574. Its totient is φ = 30721572.

The previous prime is 30721553. The next prime is 30721619. The reversal of 30721573 is 37512703.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17164449 + 13557124 = 4143^2 + 3682^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-30721573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30721553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15360786 + 15360787.

It is an arithmetic number, because the mean of its divisors is an integer number (15360787).

Almost surely, 2^30721573 is an apocalyptic number.

It is an amenable number.

30721573 is a deficient number, since it is larger than the sum of its proper divisors (1).

30721573 is an equidigital number, since it uses as much as digits as its factorization.

30721573 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4410, while the sum is 28.

The square root of 30721573 is about 5542.7044842748. The cubic root of 30721573 is about 313.1947567637.

The spelling of 30721573 in words is "thirty million, seven hundred twenty-one thousand, five hundred seventy-three".