16557281977 has 2 divisors, whose sum is σ = 16557281978. Its totient is φ = 16557281976.

The previous prime is 16557281969. The next prime is 16557281981. The reversal of 16557281977 is 77918275561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16549278736 + 8003241 = 128644^2 + 2829^2 .

It is a cyclic number.

It is not a de Polignac number, because 16557281977 - 2³ = 16557281969 is a prime.

It is not a weakly prime, because it can be changed into another prime (16557281987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8278640988 + 8278640989.

It is an arithmetic number, because the mean of its divisors is an integer number (8278640989).

Almost surely, 2^16557281977 is an apocalyptic number.

It is an amenable number.

16557281977 is a deficient number, since it is larger than the sum of its proper divisors (1).

16557281977 is an equidigital number, since it uses as much as digits as its factorization.

16557281977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7408800, while the sum is 58.

The spelling of 16557281977 in words is "sixteen billion, five hundred fifty-seven million, two hundred eighty-one thousand, nine hundred seventy-seven".