30215921 has 2 divisors, whose sum is σ = 30215922. Its totient is φ = 30215920.

The previous prime is 30215891. The next prime is 30215957. The reversal of 30215921 is 12951203.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20205025 + 10010896 = 4495^2 + 3164^2 .

It is a cyclic number.

It is not a de Polignac number, because 30215921 - 2¹⁴ = 30199537 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (30215981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15107960 + 15107961.

It is an arithmetic number, because the mean of its divisors is an integer number (15107961).

Almost surely, 2^30215921 is an apocalyptic number.

It is an amenable number.

30215921 is a deficient number, since it is larger than the sum of its proper divisors (1).

30215921 is an equidigital number, since it uses as much as digits as its factorization.

30215921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 30215921 is about 5496.9010360384. The cubic root of 30215921 is about 311.4669323109.

The spelling of 30215921 in words is "thirty million, two hundred fifteen thousand, nine hundred twenty-one".