1661616599 has 2 divisors, whose sum is σ = 1661616600. Its totient is φ = 1661616598.

The previous prime is 1661616569. The next prime is 1661616613. The reversal of 1661616599 is 9956161661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1661616599 - 2⁸ = 1661616343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1661616569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830808299 + 830808300.

It is an arithmetic number, because the mean of its divisors is an integer number (830808300).

Almost surely, 2^1661616599 is an apocalyptic number.

1661616599 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661616599 is an equidigital number, since it uses as much as digits as its factorization.

1661616599 is an evil number, because the sum of its binary digits is even.

The product of its digits is 524880, while the sum is 50.

The square root of 1661616599 is about 40762.9316781804. The cubic root of 1661616599 is about 1184.4323865038.

The spelling of 1661616599 in words is "one billion, six hundred sixty-one million, six hundred sixteen thousand, five hundred ninety-nine".