19894631657 has 2 divisors, whose sum is σ = 19894631658. Its totient is φ = 19894631656.

The previous prime is 19894631629. The next prime is 19894631671. The reversal of 19894631657 is 75613649891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17649388201 + 2245243456 = 132851^2 + 47384^2 .

It is a cyclic number.

It is not a de Polignac number, because 19894631657 - 2²² = 19890437353 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19894631596 and 19894631605.

It is not a weakly prime, because it can be changed into another prime (19894631257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9947315828 + 9947315829.

It is an arithmetic number, because the mean of its divisors is an integer number (9947315829).

Almost surely, 2^19894631657 is an apocalyptic number.

It is an amenable number.

19894631657 is a deficient number, since it is larger than the sum of its proper divisors (1).

19894631657 is an equidigital number, since it uses as much as digits as its factorization.

19894631657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9797760, while the sum is 59.

The spelling of 19894631657 in words is "nineteen billion, eight hundred ninety-four million, six hundred thirty-one thousand, six hundred fifty-seven".