1611199861 has 2 divisors, whose sum is σ = 1611199862. Its totient is φ = 1611199860.

The previous prime is 1611199847. The next prime is 1611199883. The reversal of 1611199861 is 1689911161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 883872900 + 727326961 = 29730^2 + 26969^2 .

It is an emirp because it is prime and its reverse (1689911161) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1986611191 and 1911166891.

It is a cyclic number.

It is not a de Polignac number, because 1611199861 - 2⁹ = 1611199349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1611199061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 805599930 + 805599931.

It is an arithmetic number, because the mean of its divisors is an integer number (805599931).

Almost surely, 2^1611199861 is an apocalyptic number.

It is an amenable number.

1611199861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1611199861 is an equidigital number, since it uses as much as digits as its factorization.

1611199861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 43.

The square root of 1611199861 is about 40139.7541223162. The cubic root of 1611199861 is about 1172.3298015828.

The spelling of 1611199861 in words is "one billion, six hundred eleven million, one hundred ninety-nine thousand, eight hundred sixty-one".