21673683881 has 4 divisors (see below), whose sum is σ = 21715284564. Its totient is φ = 21632083200.

The previous prime is 21673683869. The next prime is 21673683893. The reversal of 21673683881 is 18838637612.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21673683869) and next prime (21673683893).

It can be written as a sum of positive squares in 2 ways, for example, as 5320389481 + 16353294400 = 72941^2 + 127880^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21673683881 is a prime.

It is a super-2 number, since 2×21673683881² (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 (21673683181) 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, 20799560 + ... + 20800601.

It is an arithmetic number, because the mean of its divisors is an integer number (5428821141).

Almost surely, 2^21673683881 is an apocalyptic number.

It is an amenable number.

21673683881 is a deficient number, since it is larger than the sum of its proper divisors (41600683).

21673683881 is an equidigital number, since it uses as much as digits as its factorization.

21673683881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41600682.

The product of its digits is 2322432, while the sum is 53.

The spelling of 21673683881 in words is "twenty-one billion, six hundred seventy-three million, six hundred eighty-three thousand, eight hundred eighty-one".