1861688417 has 2 divisors, whose sum is σ = 1861688418. Its totient is φ = 1861688416.

The previous prime is 1861688371. The next prime is 1861688443. The reversal of 1861688417 is 7148861681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1661296081 + 200392336 = 40759^2 + 14156^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1861688417 is a prime.

It is not a weakly prime, because it can be changed into another prime (1861688467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 930844208 + 930844209.

It is an arithmetic number, because the mean of its divisors is an integer number (930844209).

Almost surely, 2^1861688417 is an apocalyptic number.

It is an amenable number.

1861688417 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861688417 is an equidigital number, since it uses as much as digits as its factorization.

1861688417 is an evil number, because the sum of its binary digits is even.

The product of its digits is 516096, while the sum is 50.

The square root of 1861688417 is about 43147.2874813701. The cubic root of 1861688417 is about 1230.1809540545.

The spelling of 1861688417 in words is "one billion, eight hundred sixty-one million, six hundred eighty-eight thousand, four hundred seventeen".