19561426905 has 16 divisors (see below), whose sum is σ = 31739105664. Its totient is φ = 10285820160.

The previous prime is 19561426903. The next prime is 19561426919. The reversal of 19561426905 is 50962416591.

It is not a de Polignac number, because 19561426905 - 2¹ = 19561426903 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19561426903) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9182704 + ... + 9184833.

It is an arithmetic number, because the mean of its divisors is an integer number (1983694104).

Almost surely, 2^19561426905 is an apocalyptic number.

19561426905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19561426905 is a deficient number, since it is larger than the sum of its proper divisors (12177678759).

19561426905 is a wasteful number, since it uses less digits than its factorization.

19561426905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18367616.

The product of its (nonzero) digits is 583200, while the sum is 48.

The spelling of 19561426905 in words is "nineteen billion, five hundred sixty-one million, four hundred twenty-six thousand, nine hundred five".