19509979886 has 4 divisors (see below), whose sum is σ = 29264969832. Its totient is φ = 9754989942.

The previous prime is 19509979871. The next prime is 19509979891. The reversal of 19509979886 is 68897990591.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4877494970 + ... + 4877494973.

It is an arithmetic number, because the mean of its divisors is an integer number (7316242458).

Almost surely, 2^19509979886 is an apocalyptic number.

19509979886 is a deficient number, since it is larger than the sum of its proper divisors (9754989946).

19509979886 is an equidigital number, since it uses as much as digits as its factorization.

19509979886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9754989945.

The product of its (nonzero) digits is 88179840, while the sum is 71.

It can be divided in two parts, 19 and 509979886, that added together give a palindrome (509979905).

The spelling of 19509979886 in words is "nineteen billion, five hundred nine million, nine hundred seventy-nine thousand, eight hundred eighty-six".