161661612407 has 2 divisors, whose sum is σ = 161661612408. Its totient is φ = 161661612406.

The previous prime is 161661612389. The next prime is 161661612433. The reversal of 161661612407 is 704216166161.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161661612407 - 2²⁸ = 161393176951 is a prime.

It is a super-2 number, since 2×161661612407² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161661612107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80830806203 + 80830806204.

It is an arithmetic number, because the mean of its divisors is an integer number (80830806204).

Almost surely, 2^161661612407 is an apocalyptic number.

161661612407 is a deficient number, since it is larger than the sum of its proper divisors (1).

161661612407 is an equidigital number, since it uses as much as digits as its factorization.

161661612407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 41.

Adding to 161661612407 its reverse (704216166161), we get a palindrome (865877778568).

The spelling of 161661612407 in words is "one hundred sixty-one billion, six hundred sixty-one million, six hundred twelve thousand, four hundred seven".