16156616821 has 2 divisors, whose sum is σ = 16156616822. Its totient is φ = 16156616820.

The previous prime is 16156616783. The next prime is 16156616837. The reversal of 16156616821 is 12861665161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8247182596 + 7909434225 = 90814^2 + 88935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16156616821 is a prime.

It is a super-2 number, since 2×16156616821² (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 (16156616881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8078308410 + 8078308411.

It is an arithmetic number, because the mean of its divisors is an integer number (8078308411).

Almost surely, 2^16156616821 is an apocalyptic number.

It is an amenable number.

16156616821 is a deficient number, since it is larger than the sum of its proper divisors (1).

16156616821 is an equidigital number, since it uses as much as digits as its factorization.

16156616821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 103680, while the sum is 43.

The spelling of 16156616821 in words is "sixteen billion, one hundred fifty-six million, six hundred sixteen thousand, eight hundred twenty-one".