21727685723 has 4 divisors (see below), whose sum is σ = 21790301880. Its totient is φ = 21665069568.

The previous prime is 21727685711. The next prime is 21727685773. The reversal of 21727685723 is 32758672712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21727685723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21727685773) 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, 31307558 + ... + 31308251.

It is an arithmetic number, because the mean of its divisors is an integer number (5447575470).

Almost surely, 2^21727685723 is an apocalyptic number.

21727685723 is a deficient number, since it is larger than the sum of its proper divisors (62616157).

21727685723 is an equidigital number, since it uses as much as digits as its factorization.

21727685723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62616156.

The product of its digits is 1975680, while the sum is 50.

The spelling of 21727685723 in words is "twenty-one billion, seven hundred twenty-seven million, six hundred eighty-five thousand, seven hundred twenty-three".