16551555121 has 2 divisors, whose sum is σ = 16551555122. Its totient is φ = 16551555120.

The previous prime is 16551555103. The next prime is 16551555131. The reversal of 16551555121 is 12155515561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16400388096 + 151167025 = 128064^2 + 12295^2 .

It is a cyclic number.

It is not a de Polignac number, because 16551555121 - 2³³ = 7961620529 is a prime.

It is not a weakly prime, because it can be changed into another prime (16551555131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8275777560 + 8275777561.

It is an arithmetic number, because the mean of its divisors is an integer number (8275777561).

Almost surely, 2^16551555121 is an apocalyptic number.

It is an amenable number.

16551555121 is a deficient number, since it is larger than the sum of its proper divisors (1).

16551555121 is an equidigital number, since it uses as much as digits as its factorization.

16551555121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37500, while the sum is 37.

The spelling of 16551555121 in words is "sixteen billion, five hundred fifty-one million, five hundred fifty-five thousand, one hundred twenty-one".