1919742661 has 2 divisors, whose sum is σ = 1919742662. Its totient is φ = 1919742660.

The previous prime is 1919742647. The next prime is 1919742703. The reversal of 1919742661 is 1662479191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1347624100 + 572118561 = 36710^2 + 23919^2 .

It is a cyclic number.

It is not a de Polignac number, because 1919742661 - 2²⁵ = 1886188229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1919742641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 959871330 + 959871331.

It is an arithmetic number, because the mean of its divisors is an integer number (959871331).

Almost surely, 2^1919742661 is an apocalyptic number.

It is an amenable number.

1919742661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1919742661 is an equidigital number, since it uses as much as digits as its factorization.

1919742661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 46.

The square root of 1919742661 is about 43814.8680358620. The cubic root of 1919742661 is about 1242.8374712820.

The spelling of 1919742661 in words is "one billion, nine hundred nineteen million, seven hundred forty-two thousand, six hundred sixty-one".