19668645381 has 32 divisors (see below), whose sum is σ = 32705906688. Its totient is φ = 10214360640.

The previous prime is 19668645343. The next prime is 19668645433. The reversal of 19668645381 is 18354686691.

It is not a de Polignac number, because 19668645381 - 2⁷ = 19668645253 is a prime.

It is a super-2 number, since 2×19668645381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19668644381) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 877591 + ... + 899723.

It is an arithmetic number, because the mean of its divisors is an integer number (1022059584).

Almost surely, 2^19668645381 is an apocalyptic number.

19668645381 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

19668645381 is a deficient number, since it is larger than the sum of its proper divisors (13037261307).

19668645381 is a wasteful number, since it uses less digits than its factorization.

19668645381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26001.

The product of its digits is 7464960, while the sum is 57.

The spelling of 19668645381 in words is "nineteen billion, six hundred sixty-eight million, six hundred forty-five thousand, three hundred eighty-one".