30720457 has 2 divisors, whose sum is σ = 30720458. Its totient is φ = 30720456.

The previous prime is 30720421. The next prime is 30720461. The reversal of 30720457 is 75402703.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29365561 + 1354896 = 5419^2 + 1164^2 .

It is an emirp because it is prime and its reverse (75402703) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30720457 - 2²³ = 22331849 is a prime.

It is not a weakly prime, because it can be changed into another prime (30720407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15360228 + 15360229.

It is an arithmetic number, because the mean of its divisors is an integer number (15360229).

Almost surely, 2^30720457 is an apocalyptic number.

It is an amenable number.

30720457 is a deficient number, since it is larger than the sum of its proper divisors (1).

30720457 is an equidigital number, since it uses as much as digits as its factorization.

30720457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5880, while the sum is 28.

The square root of 30720457 is about 5542.6038104847. The cubic root of 30720457 is about 313.1909643192.

The spelling of 30720457 in words is "thirty million, seven hundred twenty thousand, four hundred fifty-seven".