161921158724 has 12 divisors (see below), whose sum is σ = 305159106924. Its totient is φ = 74732842464.

The previous prime is 161921158703. The next prime is 161921158727. The reversal of 161921158724 is 427851129161.

It can be written as a sum of positive squares in 2 ways, for example, as 107300794624 + 54620364100 = 327568^2 + 233710^2 .

It is not an unprimeable number, because it can be changed into a prime (161921158727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1556934167 + ... + 1556934270.

It is an arithmetic number, because the mean of its divisors is an integer number (25429925577).

Almost surely, 2^161921158724 is an apocalyptic number.

It is an amenable number.

161921158724 is a deficient number, since it is larger than the sum of its proper divisors (143237948200).

161921158724 is a wasteful number, since it uses less digits than its factorization.

161921158724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3113868454 (or 3113868452 counting only the distinct ones).

The product of its digits is 241920, while the sum is 47.

The spelling of 161921158724 in words is "one hundred sixty-one billion, nine hundred twenty-one million, one hundred fifty-eight thousand, seven hundred twenty-four".