19678487691 has 4 divisors (see below), whose sum is σ = 26237983592. Its totient is φ = 13118991792.

The previous prime is 19678487659. The next prime is 19678487693.

It is a happy number.

19678487691 is nontrivially palindromic in base 10.

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

It is not a de Polignac number, because 19678487691 - 2⁵ = 19678487659 is a prime.

It is a super-2 number, since 2×19678487691² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19678487693) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3279747946 + ... + 3279747951.

It is an arithmetic number, because the mean of its divisors is an integer number (6559495898).

Almost surely, 2^19678487691 is an apocalyptic number.

19678487691 is a deficient number, since it is larger than the sum of its proper divisors (6559495901).

19678487691 is an equidigital number, since it uses as much as digits as its factorization.

19678487691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6559495900.

The product of its digits is 36578304, while the sum is 66.

The spelling of 19678487691 in words is "nineteen billion, six hundred seventy-eight million, four hundred eighty-seven thousand, six hundred ninety-one".