30728431 has 2 divisors, whose sum is σ = 30728432. Its totient is φ = 30728430.

The previous prime is 30728417. The next prime is 30728447. The reversal of 30728431 is 13482703.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 30728431 - 2¹¹ = 30726383 is a prime.

It is a super-2 number, since 2×30728431² = 1888472943443522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 30728431.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30728461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15364215 + 15364216.

It is an arithmetic number, because the mean of its divisors is an integer number (15364216).

Almost surely, 2^30728431 is an apocalyptic number.

30728431 is a deficient number, since it is larger than the sum of its proper divisors (1).

30728431 is an equidigital number, since it uses as much as digits as its factorization.

30728431 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 30728431 is about 5543.3231008124. The cubic root of 30728431 is about 313.2180599307.

The spelling of 30728431 in words is "thirty million, seven hundred twenty-eight thousand, four hundred thirty-one".