21172055723 has 32 divisors (see below), whose sum is σ = 27614079360. Its totient is φ = 15779312640.

The previous prime is 21172055713. The next prime is 21172055743. The reversal of 21172055723 is 32755027112.

It is not a de Polignac number, because 21172055723 - 2⁸ = 21172055467 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21172055713) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10361 + ... + 206037.

It is an arithmetic number, because the mean of its divisors is an integer number (862939980).

Almost surely, 2^21172055723 is an apocalyptic number.

21172055723 is a deficient number, since it is larger than the sum of its proper divisors (6442023637).

21172055723 is a wasteful number, since it uses less digits than its factorization.

21172055723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195767.

The product of its (nonzero) digits is 29400, while the sum is 35.

The spelling of 21172055723 in words is "twenty-one billion, one hundred seventy-two million, fifty-five thousand, seven hundred twenty-three".