1918891057 has 2 divisors, whose sum is σ = 1918891058. Its totient is φ = 1918891056.

The previous prime is 1918891019. The next prime is 1918891063. The reversal of 1918891057 is 7501988191.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1697357601 + 221533456 = 41199^2 + 14884^2 .

It is a cyclic number.

It is not a de Polignac number, because 1918891057 - 2²⁷ = 1784673329 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1918891057.

It is not a weakly prime, because it can be changed into another prime (1918891097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 959445528 + 959445529.

It is an arithmetic number, because the mean of its divisors is an integer number (959445529).

Almost surely, 2^1918891057 is an apocalyptic number.

It is an amenable number.

1918891057 is a deficient number, since it is larger than the sum of its proper divisors (1).

1918891057 is an equidigital number, since it uses as much as digits as its factorization.

1918891057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 49.

The square root of 1918891057 is about 43805.1487498901. The cubic root of 1918891057 is about 1242.6536685384.

The spelling of 1918891057 in words is "one billion, nine hundred eighteen million, eight hundred ninety-one thousand, fifty-seven".