16373505681 has 81 divisors (see below), whose sum is σ = 27346607379. Its totient is φ = 9434161152.

The previous prime is 16373505641. The next prime is 16373505691. The reversal of 16373505681 is 18650537361.

The square root of 16373505681 is 127959.

It is a perfect power (a square), and thus also a powerful number.

16373505681 is a `hidden beast` number, since 1 + 6 + 37 + 3 + 50 + 568 + 1 = 666.

It can be written as a sum of positive squares in 13 ways, for example, as 13657428225 + 2716077456 = 116865^2 + 52116^2 .

It is not a de Polignac number, because 16373505681 - 2¹¹ = 16373503633 is a prime.

It is a super-2 number, since 2×16373505681² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (16373505641) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 84836721 + ... + 84836913.

Almost surely, 2^16373505681 is an apocalyptic number.

16373505681 is the 127959-th square number.

16373505681 is the 63980-th centered octagonal number.

It is an amenable number.

16373505681 is a deficient number, since it is larger than the sum of its proper divisors (10973101698).

16373505681 is a wasteful number, since it uses less digits than its factorization.

16373505681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 452 (or 226 counting only the distinct ones).

The product of its (nonzero) digits is 453600, while the sum is 45.

The spelling of 16373505681 in words is "sixteen billion, three hundred seventy-three million, five hundred five thousand, six hundred eighty-one".