19987023157 has 2 divisors, whose sum is σ = 19987023158. Its totient is φ = 19987023156.

The previous prime is 19987023149. The next prime is 19987023169. The reversal of 19987023157 is 75132078991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19701210321 + 285812836 = 140361^2 + 16906^2 .

It is a cyclic number.

It is not a de Polignac number, because 19987023157 - 2³ = 19987023149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19987023127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9993511578 + 9993511579.

It is an arithmetic number, because the mean of its divisors is an integer number (9993511579).

Almost surely, 2^19987023157 is an apocalyptic number.

It is an amenable number.

19987023157 is a deficient number, since it is larger than the sum of its proper divisors (1).

19987023157 is an equidigital number, since it uses as much as digits as its factorization.

19987023157 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 952560, while the sum is 52.

The spelling of 19987023157 in words is "nineteen billion, nine hundred eighty-seven million, twenty-three thousand, one hundred fifty-seven".