1391891431 has 4 divisors (see below), whose sum is σ = 1590733072. Its totient is φ = 1193049792.

The previous prime is 1391891429. The next prime is 1391891461. The reversal of 1391891431 is 1341981931.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1391891431 - 2¹ = 1391891429 is a prime.

It is a super-2 number, since 2×1391891431² = 3874723511382455522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1391891461) 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 in 3 ways as a sum of consecutive naturals, for example, 99420810 + ... + 99420823.

It is an arithmetic number, because the mean of its divisors is an integer number (397683268).

Almost surely, 2^1391891431 is an apocalyptic number.

1391891431 is a deficient number, since it is larger than the sum of its proper divisors (198841641).

1391891431 is an equidigital number, since it uses as much as digits as its factorization.

1391891431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198841640.

The product of its digits is 23328, while the sum is 40.

The square root of 1391891431 is about 37308.0612066615. The cubic root of 1391891431 is about 1116.5250050437.

The spelling of 1391891431 in words is "one billion, three hundred ninety-one million, eight hundred ninety-one thousand, four hundred thirty-one".