21651895321 has 8 divisors (see below), whose sum is σ = 24755155200. Its totient is φ = 18551168448.

The previous prime is 21651895289. The next prime is 21651895333. The reversal of 21651895321 is 12359815612.

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 21651895321 - 2⁵ = 21651895289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21651895361) 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, 614896 + ... + 649153.

It is an arithmetic number, because the mean of its divisors is an integer number (3094394400).

Almost surely, 2^21651895321 is an apocalyptic number.

It is an amenable number.

21651895321 is a deficient number, since it is larger than the sum of its proper divisors (3103259879).

21651895321 is a wasteful number, since it uses less digits than its factorization.

21651895321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1266503.

The product of its digits is 129600, while the sum is 43.

The spelling of 21651895321 in words is "twenty-one billion, six hundred fifty-one million, eight hundred ninety-five thousand, three hundred twenty-one".