30128257 has 4 divisors (see below), whose sum is σ = 30170880. Its totient is φ = 30085636.

The previous prime is 30128239. The next prime is 30128299. The reversal of 30128257 is 75282103.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 30128257 - 2¹⁵ = 30095489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (30128557) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20233 + ... + 21670.

It is an arithmetic number, because the mean of its divisors is an integer number (7542720).

Almost surely, 2^30128257 is an apocalyptic number.

It is an amenable number.

30128257 is a deficient number, since it is larger than the sum of its proper divisors (42623).

30128257 is an equidigital number, since it uses as much as digits as its factorization.

30128257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42622.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 30128257 is about 5488.9212965755. The cubic root of 30128257 is about 311.1654258581.

The spelling of 30128257 in words is "thirty million, one hundred twenty-eight thousand, two hundred fifty-seven".