1931661361 has 4 divisors (see below), whose sum is σ = 2207612992. Its totient is φ = 1655709732.

The previous prime is 1931661349. The next prime is 1931661379. The reversal of 1931661361 is 1631661391.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1931661361 - 2¹⁵ = 1931628593 is a prime.

It is a super-2 number, since 2×1931661361² = 7462631227160744642, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1931661361.

It is not an unprimeable number, because it can be changed into a prime (1931661341) 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 in 3 ways as a sum of consecutive naturals, for example, 137975805 + ... + 137975818.

It is an arithmetic number, because the mean of its divisors is an integer number (551903248).

Almost surely, 2^1931661361 is an apocalyptic number.

It is an amenable number.

1931661361 is a deficient number, since it is larger than the sum of its proper divisors (275951631).

1931661361 is an equidigital number, since it uses as much as digits as its factorization.

1931661361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275951630.

The product of its digits is 17496, while the sum is 37.

The square root of 1931661361 is about 43950.6696308486. The cubic root of 1931661361 is about 1245.4042140559.

The spelling of 1931661361 in words is "one billion, nine hundred thirty-one million, six hundred sixty-one thousand, three hundred sixty-one".