21991227254 has 4 divisors (see below), whose sum is σ = 32986840884. Its totient is φ = 10995613626.

The previous prime is 21991227253. The next prime is 21991227329. The reversal of 21991227254 is 45272219912.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21991227254² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21991227253) 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 as a sum of consecutive naturals, namely, 5497806812 + ... + 5497806815.

It is an arithmetic number, because the mean of its divisors is an integer number (8246710221).

Almost surely, 2^21991227254 is an apocalyptic number.

21991227254 is a deficient number, since it is larger than the sum of its proper divisors (10995613630).

21991227254 is a wasteful number, since it uses less digits than its factorization.

21991227254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10995613629.

The product of its digits is 181440, while the sum is 44.

The spelling of 21991227254 in words is "twenty-one billion, nine hundred ninety-one million, two hundred twenty-seven thousand, two hundred fifty-four".