1931381 has 2 divisors, whose sum is σ = 1931382. Its totient is φ = 1931380.

The previous prime is 1931357. The next prime is 1931383. The reversal of 1931381 is 1831391.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1276900 + 654481 = 1130^2 + 809^2 .

It is a cyclic number.

It is not a de Polignac number, because 1931381 - 2⁶ = 1931317 is a prime.

It is a super-2 number, since 2×1931381² = 7460465134322, which contains 22 as substring.

Together with 1931383, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1931381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1931383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 965690 + 965691.

It is an arithmetic number, because the mean of its divisors is an integer number (965691).

2^1931381 is an apocalyptic number.

It is an amenable number.

1931381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1931381 is an equidigital number, since it uses as much as digits as its factorization.

1931381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 26.

The square root of 1931381 is about 1389.7413428405. The cubic root of 1931381 is about 124.5343958556.

The spelling of 1931381 in words is "one million, nine hundred thirty-one thousand, three hundred eighty-one".