161681621075 has 24 divisors (see below), whose sum is σ = 216023236128. Its totient is φ = 119331463680.

The previous prime is 161681621069. The next prime is 161681621107. The reversal of 161681621075 is 570126186161.

It is not a de Polignac number, because 161681621075 - 2¹⁴ = 161681604691 is a prime.

It is a super-2 number, since 2×161681621075² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 475922 + ... + 741528.

It is an arithmetic number, because the mean of its divisors is an integer number (9000968172).

Almost surely, 2^161681621075 is an apocalyptic number.

161681621075 is a deficient number, since it is larger than the sum of its proper divisors (54341615053).

161681621075 is a wasteful number, since it uses less digits than its factorization.

161681621075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267503 (or 267498 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 44.

The spelling of 161681621075 in words is "one hundred sixty-one billion, six hundred eighty-one million, six hundred twenty-one thousand, seventy-five".