1931221379 has 2 divisors, whose sum is σ = 1931221380. Its totient is φ = 1931221378.

The previous prime is 1931221373. The next prime is 1931221393. The reversal of 1931221379 is 9731221391.

It is a weak prime.

It is an emirp because it is prime and its reverse (9731221391) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1931221379 - 2⁴ = 1931221363 is a prime.

It is a zygodrome in base 2.

It is not a weakly prime, because it can be changed into another prime (1931221373) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 965610689 + 965610690.

It is an arithmetic number, because the mean of its divisors is an integer number (965610690).

Almost surely, 2^1931221379 is an apocalyptic number.

1931221379 is a deficient number, since it is larger than the sum of its proper divisors (1).

1931221379 is an equidigital number, since it uses as much as digits as its factorization.

1931221379 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20412, while the sum is 38.

The square root of 1931221379 is about 43945.6639385503. The cubic root of 1931221379 is about 1245.3096500265.

The spelling of 1931221379 in words is "one billion, nine hundred thirty-one million, two hundred twenty-one thousand, three hundred seventy-nine".