19871617651 has 2 divisors, whose sum is σ = 19871617652. Its totient is φ = 19871617650.

The previous prime is 19871617643. The next prime is 19871617663. The reversal of 19871617651 is 15671617891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19871617651 - 2³ = 19871617643 is a prime.

It is not a weakly prime, because it can be changed into another prime (19871617631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9935808825 + 9935808826.

It is an arithmetic number, because the mean of its divisors is an integer number (9935808826).

Almost surely, 2^19871617651 is an apocalyptic number.

19871617651 is a deficient number, since it is larger than the sum of its proper divisors (1).

19871617651 is an equidigital number, since it uses as much as digits as its factorization.

19871617651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 635040, while the sum is 52.

The spelling of 19871617651 in words is "nineteen billion, eight hundred seventy-one million, six hundred seventeen thousand, six hundred fifty-one".