1897989161 has 2 divisors, whose sum is σ = 1897989162. Its totient is φ = 1897989160.

The previous prime is 1897989151. The next prime is 1897989209. The reversal of 1897989161 is 1619897981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 956726761 + 941262400 = 30931^2 + 30680^2 .

It is a cyclic number.

It is not a de Polignac number, because 1897989161 - 2¹⁴ = 1897972777 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1897989161.

It is not a weakly prime, because it can be changed into another prime (1897989101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 948994580 + 948994581.

It is an arithmetic number, because the mean of its divisors is an integer number (948994581).

Almost surely, 2^1897989161 is an apocalyptic number.

It is an amenable number.

1897989161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1897989161 is an equidigital number, since it uses as much as digits as its factorization.

1897989161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1959552, while the sum is 59.

The square root of 1897989161 is about 43565.9174240598. The cubic root of 1897989161 is about 1238.1252368992.

The spelling of 1897989161 in words is "one billion, eight hundred ninety-seven million, nine hundred eighty-nine thousand, one hundred sixty-one".