19949564777 has 4 divisors (see below), whose sum is σ = 20012497476. Its totient is φ = 19886632080.

The previous prime is 19949564741. The next prime is 19949564797. The reversal of 19949564777 is 77746594991.

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 11011564096 + 8938000681 = 104936^2 + 94541^2 .

It is a cyclic number.

It is not a de Polignac number, because 19949564777 - 2¹⁴ = 19949548393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19949564707) 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, 31465874 + ... + 31466507.

It is an arithmetic number, because the mean of its divisors is an integer number (5003124369).

Almost surely, 2^19949564777 is an apocalyptic number.

It is an amenable number.

19949564777 is a deficient number, since it is larger than the sum of its proper divisors (62932699).

19949564777 is an equidigital number, since it uses as much as digits as its factorization.

19949564777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62932698.

The product of its digits is 120022560, while the sum is 68.

The spelling of 19949564777 in words is "nineteen billion, nine hundred forty-nine million, five hundred sixty-four thousand, seven hundred seventy-seven".