21857728573 has 16 divisors (see below), whose sum is σ = 23206256640. Its totient is φ = 20529255600.

The previous prime is 21857728549. The next prime is 21857728601. The reversal of 21857728573 is 37582775812.

It is a cyclic number.

It is not a de Polignac number, because 21857728573 - 2²⁹ = 21320857661 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 (21857726573) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4657158 + ... + 4661848.

It is an arithmetic number, because the mean of its divisors is an integer number (1450391040).

Almost surely, 2^21857728573 is an apocalyptic number.

It is an amenable number.

21857728573 is a deficient number, since it is larger than the sum of its proper divisors (1348528067).

21857728573 is a wasteful number, since it uses less digits than its factorization.

21857728573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6768.

The product of its digits is 6585600, while the sum is 55.

The spelling of 21857728573 in words is "twenty-one billion, eight hundred fifty-seven million, seven hundred twenty-eight thousand, five hundred seventy-three".