19823572981 has 4 divisors (see below), whose sum is σ = 19968270732. Its totient is φ = 19678875232.

The previous prime is 19823572969. The next prime is 19823572999. The reversal of 19823572981 is 18927532891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18927532891 = 37 ⋅511554943.

It can be written as a sum of positive squares in 2 ways, for example, as 12221302500 + 7602270481 = 110550^2 + 87191^2 .

It is a cyclic number.

It is not a de Polignac number, because 19823572981 - 2²⁷ = 19689355253 is a prime.

It is a super-2 number, since 2×19823572981² (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 (19823572921) 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, 72348670 + ... + 72348943.

It is an arithmetic number, because the mean of its divisors is an integer number (4992067683).

Almost surely, 2^19823572981 is an apocalyptic number.

It is an amenable number.

19823572981 is a deficient number, since it is larger than the sum of its proper divisors (144697751).

19823572981 is a wasteful number, since it uses less digits than its factorization.

19823572981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144697750.

The product of its digits is 2177280, while the sum is 55.

It can be divided in two parts, 198235 and 72981, that added together give a triangular number (271216 = T₇₃₆).

The spelling of 19823572981 in words is "nineteen billion, eight hundred twenty-three million, five hundred seventy-two thousand, nine hundred eighty-one".