18821468081 has 4 divisors (see below), whose sum is σ = 20269273332. Its totient is φ = 17373662832.

The previous prime is 18821468063. The next prime is 18821468087. The reversal of 18821468081 is 18086412881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18086412881 = 46811 ⋅386371.

It can be written as a sum of positive squares in 2 ways, for example, as 6461587456 + 12359880625 = 80384^2 + 111175^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18821468081 is a prime.

It is a super-2 number, since 2×18821468081² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18821468087) 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, 723902606 + ... + 723902631.

It is an arithmetic number, because the mean of its divisors is an integer number (5067318333).

Almost surely, 2^18821468081 is an apocalyptic number.

It is an amenable number.

18821468081 is a deficient number, since it is larger than the sum of its proper divisors (1447805251).

18821468081 is a wasteful number, since it uses less digits than its factorization.

18821468081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1447805250.

The product of its (nonzero) digits is 196608, while the sum is 47.

The spelling of 18821468081 in words is "eighteen billion, eight hundred twenty-one million, four hundred sixty-eight thousand, eighty-one".