21657236573 has 8 divisors (see below), whose sum is σ = 24879373248. Its totient is φ = 18467161344.

The previous prime is 21657236551. The next prime is 21657236617. The reversal of 21657236573 is 37563275612.

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 21657236573 - 2¹⁸ = 21656974429 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 (21657236533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8013911 + ... + 8016612.

It is an arithmetic number, because the mean of its divisors is an integer number (3109921656).

Almost surely, 2^21657236573 is an apocalyptic number.

It is an amenable number.

21657236573 is a deficient number, since it is larger than the sum of its proper divisors (3222136675).

21657236573 is a wasteful number, since it uses less digits than its factorization.

21657236573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16030723.

The product of its digits is 1587600, while the sum is 47.

The spelling of 21657236573 in words is "twenty-one billion, six hundred fifty-seven million, two hundred thirty-six thousand, five hundred seventy-three".