391241387 has 2 divisors, whose sum is σ = 391241388. Its totient is φ = 391241386.

The previous prime is 391241371. The next prime is 391241399. The reversal of 391241387 is 783142193.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 391241387 - 2⁴ = 391241371 is a prime.

It is equal to p_20893817 and since 391241387 and 20893817 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 391241387.

It is not a weakly prime, because it can be changed into another prime (391241317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195620693 + 195620694.

It is an arithmetic number, because the mean of its divisors is an integer number (195620694).

Almost surely, 2^391241387 is an apocalyptic number.

391241387 is a deficient number, since it is larger than the sum of its proper divisors (1).

391241387 is an equidigital number, since it uses as much as digits as its factorization.

391241387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 38.

The square root of 391241387 is about 19779.8227241803. The cubic root of 391241387 is about 731.3887288162.

The spelling of 391241387 in words is "three hundred ninety-one million, two hundred forty-one thousand, three hundred eighty-seven".