16651556503 has 2 divisors, whose sum is σ = 16651556504. Its totient is φ = 16651556502.

The previous prime is 16651556501. The next prime is 16651556561. The reversal of 16651556503 is 30565515661.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16651556503 - 2¹ = 16651556501 is a prime.

Together with 16651556501, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 16651556503.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16651556501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8325778251 + 8325778252.

It is an arithmetic number, because the mean of its divisors is an integer number (8325778252).

Almost surely, 2^16651556503 is an apocalyptic number.

16651556503 is a deficient number, since it is larger than the sum of its proper divisors (1).

16651556503 is an equidigital number, since it uses as much as digits as its factorization.

16651556503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 405000, while the sum is 43.

The spelling of 16651556503 in words is "sixteen billion, six hundred fifty-one million, five hundred fifty-six thousand, five hundred three".