19897490786 has 4 divisors (see below), whose sum is σ = 29846236182. Its totient is φ = 9948745392.

The previous prime is 19897490741. The next prime is 19897490827. The reversal of 19897490786 is 68709479891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 68709479891 = 13 ⋅5285344607.

It can be written as a sum of positive squares in only one way, i.e., 11411580625 + 8485910161 = 106825^2 + 92119^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4974372695 + ... + 4974372698.

Almost surely, 2^19897490786 is an apocalyptic number.

19897490786 is a deficient number, since it is larger than the sum of its proper divisors (9948745396).

19897490786 is an equidigital number, since it uses as much as digits as its factorization.

19897490786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9948745395.

The product of its (nonzero) digits is 54867456, while the sum is 68.

The spelling of 19897490786 in words is "nineteen billion, eight hundred ninety-seven million, four hundred ninety thousand, seven hundred eighty-six".