21271822251 has 16 divisors (see below), whose sum is σ = 29777162496. Its totient is φ = 13481414496.

The previous prime is 21271822241. The next prime is 21271822279. The reversal of 21271822251 is 15222817212.

It is not a de Polignac number, because 21271822251 - 2⁷ = 21271822123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21271822241) 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, 934420 + ... + 956913.

It is an arithmetic number, because the mean of its divisors is an integer number (1861072656).

Almost surely, 2^21271822251 is an apocalyptic number.

21271822251 is a deficient number, since it is larger than the sum of its proper divisors (8505340245).

21271822251 is a wasteful number, since it uses less digits than its factorization.

21271822251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1891522.

The product of its digits is 8960, while the sum is 33.

The spelling of 21271822251 in words is "twenty-one billion, two hundred seventy-one million, eight hundred twenty-two thousand, two hundred fifty-one".