21165246424 has 64 divisors (see below), whose sum is σ = 46445414400. Its totient is φ = 8853611904.

The previous prime is 21165246413. The next prime is 21165246451. The reversal of 21165246424 is 42464256112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 970957 + ... + 992515.

It is an arithmetic number, because the mean of its divisors is an integer number (725709600).

Almost surely, 2^21165246424 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21165246424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23222707200).

21165246424 is an abundant number, since it is smaller than the sum of its proper divisors (25280167976).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21165246424 is a wasteful number, since it uses less digits than its factorization.

21165246424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21992 (or 21988 counting only the distinct ones).

The product of its digits is 92160, while the sum is 37.

The spelling of 21165246424 in words is "twenty-one billion, one hundred sixty-five million, two hundred forty-six thousand, four hundred twenty-four".