21171243055 has 8 divisors (see below), whose sum is σ = 25406506512. Its totient is φ = 16936317888.

The previous prime is 21171243043. The next prime is 21171243059. The reversal of 21171243055 is 55034217112.

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

It is a cyclic number.

It is not a de Polignac number, because 21171243055 - 2²¹ = 21169145903 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21171243059) 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, 83472 + ... + 222058.

It is an arithmetic number, because the mean of its divisors is an integer number (3175813314).

Almost surely, 2^21171243055 is an apocalyptic number.

21171243055 is a deficient number, since it is larger than the sum of its proper divisors (4235263457).

21171243055 is a wasteful number, since it uses less digits than its factorization.

21171243055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169145.

The product of its (nonzero) digits is 8400, while the sum is 31.

The spelling of 21171243055 in words is "twenty-one billion, one hundred seventy-one million, two hundred forty-three thousand, fifty-five".