161618651945 has 16 divisors (see below), whose sum is σ = 195007026960. Its totient is φ = 128586931200.

The previous prime is 161618651839. The next prime is 161618651947. The reversal of 161618651945 is 549156816161.

It can be written as a sum of positive squares in 8 ways, for example, as 933119209 + 160685532736 = 30547^2 + 400856^2 .

It is not a de Polignac number, because 161618651945 - 2¹⁴ = 161618635561 is a prime.

It is a super-2 number, since 2×161618651945² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161618651947) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 621611 + ... + 842399.

It is an arithmetic number, because the mean of its divisors is an integer number (12187939185).

Almost surely, 2^161618651945 is an apocalyptic number.

It is an amenable number.

161618651945 is a deficient number, since it is larger than the sum of its proper divisors (33388375015).

161618651945 is a wasteful number, since it uses less digits than its factorization.

161618651945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221596.

The product of its digits is 1555200, while the sum is 53.

The spelling of 161618651945 in words is "one hundred sixty-one billion, six hundred eighteen million, six hundred fifty-one thousand, nine hundred forty-five".