21544940181 has 8 divisors (see below), whose sum is σ = 28728322240. Its totient is φ = 14362425792.

The previous prime is 21544940171. The next prime is 21544940189. The reversal of 21544940181 is 18104944512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21544940181 - 2²⁷ = 21410722453 is a prime.

It is a super-2 number, since 2×21544940181² (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 (21544940189) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 156580 + ... + 260013.

It is an arithmetic number, because the mean of its divisors is an integer number (3591040280).

Almost surely, 2^21544940181 is an apocalyptic number.

It is an amenable number.

21544940181 is a deficient number, since it is larger than the sum of its proper divisors (7183382059).

21544940181 is a wasteful number, since it uses less digits than its factorization.

21544940181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433835.

The product of its (nonzero) digits is 46080, while the sum is 39.

The spelling of 21544940181 in words is "twenty-one billion, five hundred forty-four million, nine hundred forty thousand, one hundred eighty-one".