30891391 has 2 divisors, whose sum is σ = 30891392. Its totient is φ = 30891390.

The previous prime is 30891349. The next prime is 30891401. The reversal of 30891391 is 19319803.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 30891391 - 2¹³ = 30883199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30892391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15445695 + 15445696.

It is an arithmetic number, because the mean of its divisors is an integer number (15445696).

Almost surely, 2^30891391 is an apocalyptic number.

30891391 is a deficient number, since it is larger than the sum of its proper divisors (1).

30891391 is an equidigital number, since it uses as much as digits as its factorization.

30891391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 30891391 is about 5558.0024289307. The cubic root of 30891391 is about 313.7707733742.

The spelling of 30891391 in words is "thirty million, eight hundred ninety-one thousand, three hundred ninety-one".