391131281 has 2 divisors, whose sum is σ = 391131282. Its totient is φ = 391131280.

The previous prime is 391131271. The next prime is 391131317. The reversal of 391131281 is 182131193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 391050625 + 80656 = 19775^2 + 284^2 .

It is a cyclic number.

It is not a de Polignac number, because 391131281 - 2⁶ = 391131217 is a prime.

It is a super-2 number, since 2×391131281² = 305967357953401922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (391131241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195565640 + 195565641.

It is an arithmetic number, because the mean of its divisors is an integer number (195565641).

Almost surely, 2^391131281 is an apocalyptic number.

It is an amenable number.

391131281 is a deficient number, since it is larger than the sum of its proper divisors (1).

391131281 is an equidigital number, since it uses as much as digits as its factorization.

391131281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 29.

The square root of 391131281 is about 19777.0392374592. The cubic root of 391131281 is about 731.3201114649.

The spelling of 391131281 in words is "three hundred ninety-one million, one hundred thirty-one thousand, two hundred eighty-one".