19712693561 has 4 divisors (see below), whose sum is σ = 21504756624. Its totient is φ = 17920630500.

The previous prime is 19712693551. The next prime is 19712693573. The reversal of 19712693561 is 16539621791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19712693561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19712693551) 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, 896031515 + ... + 896031536.

It is an arithmetic number, because the mean of its divisors is an integer number (5376189156).

Almost surely, 2^19712693561 is an apocalyptic number.

19712693561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

19712693561 is a deficient number, since it is larger than the sum of its proper divisors (1792063063).

19712693561 is a wasteful number, since it uses less digits than its factorization.

19712693561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1792063062.

The product of its digits is 612360, while the sum is 50.

The spelling of 19712693561 in words is "nineteen billion, seven hundred twelve million, six hundred ninety-three thousand, five hundred sixty-one".