21723541277 has 4 divisors (see below), whose sum is σ = 21749746620. Its totient is φ = 21697335936.

The previous prime is 21723541249. The next prime is 21723541291. The reversal of 21723541277 is 77214532712.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14576698756 + 7146842521 = 120734^2 + 84539^2 .

It is a cyclic number.

It is not a de Polignac number, because 21723541277 - 2²⁸ = 21455105821 is a prime.

It is a super-2 number, since 2×21723541277² (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 (21723544277) 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, 13101428 + ... + 13103085.

It is an arithmetic number, because the mean of its divisors is an integer number (5437436655).

Almost surely, 2^21723541277 is an apocalyptic number.

It is an amenable number.

21723541277 is a deficient number, since it is larger than the sum of its proper divisors (26205343).

21723541277 is an equidigital number, since it uses as much as digits as its factorization.

21723541277 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26205342.

The product of its digits is 164640, while the sum is 41.

The spelling of 21723541277 in words is "twenty-one billion, seven hundred twenty-three million, five hundred forty-one thousand, two hundred seventy-seven".