16615333981 has 2 divisors, whose sum is σ = 16615333982. Its totient is φ = 16615333980.

The previous prime is 16615333967. The next prime is 16615334053. The reversal of 16615333981 is 18933351661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14239648900 + 2375685081 = 119330^2 + 48741^2 .

It is a cyclic number.

It is not a de Polignac number, because 16615333981 - 2⁵ = 16615333949 is a prime.

It is a super-2 number, since 2×16615333981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16615333901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8307666990 + 8307666991.

It is an arithmetic number, because the mean of its divisors is an integer number (8307666991).

Almost surely, 2^16615333981 is an apocalyptic number.

It is an amenable number.

16615333981 is a deficient number, since it is larger than the sum of its proper divisors (1).

16615333981 is an equidigital number, since it uses as much as digits as its factorization.

16615333981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 349920, while the sum is 46.

The spelling of 16615333981 in words is "sixteen billion, six hundred fifteen million, three hundred thirty-three thousand, nine hundred eighty-one".