30970721 has 2 divisors, whose sum is σ = 30970722. Its totient is φ = 30970720.

The previous prime is 30970691. The next prime is 30970727. The reversal of 30970721 is 12707903.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30913600 + 57121 = 5560^2 + 239^2 .

It is a cyclic number.

It is not a de Polignac number, because 30970721 - 2¹⁸ = 30708577 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (30970727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15485360 + 15485361.

It is an arithmetic number, because the mean of its divisors is an integer number (15485361).

Almost surely, 2^30970721 is an apocalyptic number.

It is an amenable number.

30970721 is a deficient number, since it is larger than the sum of its proper divisors (1).

30970721 is an equidigital number, since it uses as much as digits as its factorization.

30970721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2646, while the sum is 29.

The square root of 30970721 is about 5565.1344098773. The cubic root of 30970721 is about 314.0391346412.

The spelling of 30970721 in words is "thirty million, nine hundred seventy thousand, seven hundred twenty-one".