21324552891 has 16 divisors (see below), whose sum is σ = 30034976640. Its totient is φ = 13420537920.

The previous prime is 21324552857. The next prime is 21324552901. The reversal of 21324552891 is 19825542312.

It is not a de Polignac number, because 21324552891 - 2¹⁷ = 21324421819 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21324551891) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 644850 + ... + 677111.

It is an arithmetic number, because the mean of its divisors is an integer number (1877186040).

Almost surely, 2^21324552891 is an apocalyptic number.

21324552891 is a deficient number, since it is larger than the sum of its proper divisors (8710423749).

21324552891 is a wasteful number, since it uses less digits than its factorization.

21324552891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1322266.

The product of its digits is 172800, while the sum is 42.

The spelling of 21324552891 in words is "twenty-one billion, three hundred twenty-four million, five hundred fifty-two thousand, eight hundred ninety-one".