16556425649 has 2 divisors, whose sum is σ = 16556425650. Its totient is φ = 16556425648.

The previous prime is 16556425643. The next prime is 16556425667. The reversal of 16556425649 is 94652465561.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11933377600 + 4623048049 = 109240^2 + 67993^2 .

It is a cyclic number.

It is not a de Polignac number, because 16556425649 - 2⁸ = 16556425393 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16556425649.

It is not a weakly prime, because it can be changed into another prime (16556425643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8278212824 + 8278212825.

It is an arithmetic number, because the mean of its divisors is an integer number (8278212825).

Almost surely, 2^16556425649 is an apocalyptic number.

It is an amenable number.

16556425649 is a deficient number, since it is larger than the sum of its proper divisors (1).

16556425649 is an equidigital number, since it uses as much as digits as its factorization.

16556425649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776000, while the sum is 53.

The spelling of 16556425649 in words is "sixteen billion, five hundred fifty-six million, four hundred twenty-five thousand, six hundred forty-nine".