16081655921 has 4 divisors (see below), whose sum is σ = 16085551092. Its totient is φ = 16077760752.

The previous prime is 16081655897. The next prime is 16081655923. The reversal of 16081655921 is 12955618061.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12955618061 = 38639 ⋅335299.

It can be written as a sum of positive squares in 2 ways, for example, as 10870981696 + 5210674225 = 104264^2 + 72185^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16081655921 is a prime.

It is a super-2 number, since 2×16081655921² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16081655923) 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, 1941386 + ... + 1949651.

It is an arithmetic number, because the mean of its divisors is an integer number (4021387773).

Almost surely, 2^16081655921 is an apocalyptic number.

It is an amenable number.

16081655921 is a deficient number, since it is larger than the sum of its proper divisors (3895171).

16081655921 is an equidigital number, since it uses as much as digits as its factorization.

16081655921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3895170.

The product of its (nonzero) digits is 129600, while the sum is 44.

The spelling of 16081655921 in words is "sixteen billion, eighty-one million, six hundred fifty-five thousand, nine hundred twenty-one".