201566616651 has 24 divisors (see below), whose sum is σ = 308443384080. Its totient is φ = 126405467136.

The previous prime is 201566616637. The next prime is 201566616661. The reversal of 201566616651 is 156616665102.

It is not a de Polignac number, because 201566616651 - 2⁵ = 201566616619 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 201566616597 and 201566616606.

It is not an unprimeable number, because it can be changed into a prime (201566616631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 65121 + ... + 638258.

It is an arithmetic number, because the mean of its divisors is an integer number (12851807670).

Almost surely, 2^201566616651 is an apocalyptic number.

201566616651 is a deficient number, since it is larger than the sum of its proper divisors (106876767429).

201566616651 is a wasteful number, since it uses less digits than its factorization.

201566616651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 705275 (or 705272 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 45.

The spelling of 201566616651 in words is "two hundred one billion, five hundred sixty-six million, six hundred sixteen thousand, six hundred fifty-one".