19687158457 has 4 divisors (see below), whose sum is σ = 20366026020. Its totient is φ = 19008290896.

The previous prime is 19687158377. The next prime is 19687158467. The reversal of 19687158457 is 75485178691.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9349149481 + 10338008976 = 96691^2 + 101676^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19687158457 is a prime.

It is a super-2 number, since 2×19687158457² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19687158395 and 19687158404.

It is not an unprimeable number, because it can be changed into a prime (19687158467) 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 in 3 ways as a sum of consecutive naturals, for example, 339433738 + ... + 339433795.

It is an arithmetic number, because the mean of its divisors is an integer number (5091506505).

Almost surely, 2^19687158457 is an apocalyptic number.

It is an amenable number.

19687158457 is a deficient number, since it is larger than the sum of its proper divisors (678867563).

19687158457 is an equidigital number, since it uses as much as digits as its factorization.

19687158457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 678867562.

The product of its digits is 16934400, while the sum is 61.

The spelling of 19687158457 in words is "nineteen billion, six hundred eighty-seven million, one hundred fifty-eight thousand, four hundred fifty-seven".