19875837781 has 4 divisors (see below), whose sum is σ = 19891379200. Its totient is φ = 19860296364.

The previous prime is 19875837749. The next prime is 19875837809. The reversal of 19875837781 is 18773857891.

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 not a de Polignac number, because 19875837781 - 2⁵ = 19875837749 is a prime.

It is a super-2 number, since 2×19875837781² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19875837881) 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, 7768791 + ... + 7771348.

It is an arithmetic number, because the mean of its divisors is an integer number (4972844800).

Almost surely, 2^19875837781 is an apocalyptic number.

It is an amenable number.

19875837781 is a deficient number, since it is larger than the sum of its proper divisors (15541419).

19875837781 is a wasteful number, since it uses less digits than its factorization.

19875837781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15541418.

The product of its digits is 23708160, while the sum is 64.

The spelling of 19875837781 in words is "nineteen billion, eight hundred seventy-five million, eight hundred thirty-seven thousand, seven hundred eighty-one".