21273457723 has 16 divisors (see below), whose sum is σ = 24367682304. Its totient is φ = 18193079520.

The previous prime is 21273457693. The next prime is 21273457727. The reversal of 21273457723 is 32775437212.

It is a happy number.

It is not a de Polignac number, because 21273457723 - 2²⁹ = 20736586811 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21273457723.

It is not an unprimeable number, because it can be changed into a prime (21273457727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9382836 + ... + 9385102.

It is an arithmetic number, because the mean of its divisors is an integer number (1522980144).

Almost surely, 2^21273457723 is an apocalyptic number.

21273457723 is a deficient number, since it is larger than the sum of its proper divisors (3094224581).

21273457723 is a wasteful number, since it uses less digits than its factorization.

21273457723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4722.

The product of its digits is 493920, while the sum is 43.

The spelling of 21273457723 in words is "twenty-one billion, two hundred seventy-three million, four hundred fifty-seven thousand, seven hundred twenty-three".