21254323657 has 8 divisors (see below), whose sum is σ = 24293781056. Its totient is φ = 18215647632.

The previous prime is 21254323579. The next prime is 21254323663. The reversal of 21254323657 is 75632345212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21254323657 - 2¹¹ = 21254321609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21254324657) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 135843 + ... + 246904.

It is an arithmetic number, because the mean of its divisors is an integer number (3036722632).

Almost surely, 2^21254323657 is an apocalyptic number.

It is an amenable number.

21254323657 is a deficient number, since it is larger than the sum of its proper divisors (3039457399).

21254323657 is an equidigital number, since it uses as much as digits as its factorization.

21254323657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390687.

The product of its digits is 302400, while the sum is 40.

Adding to 21254323657 its reverse (75632345212), we get a palindrome (96886668869).

The spelling of 21254323657 in words is "twenty-one billion, two hundred fifty-four million, three hundred twenty-three thousand, six hundred fifty-seven".