21421505244 has 24 divisors (see below), whose sum is σ = 50011532928. Its totient is φ = 7136498800.

The previous prime is 21421505233. The next prime is 21421505249. The reversal of 21421505244 is 44250512412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421505249) 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, 478032 + ... + 520919.

It is an arithmetic number, because the mean of its divisors is an integer number (2083813872).

Almost surely, 2^21421505244 is an apocalyptic number.

It is an amenable number.

21421505244 is an abundant number, since it is smaller than the sum of its proper divisors (28590027684).

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

21421505244 is a wasteful number, since it uses less digits than its factorization.

21421505244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000745 (or 1000743 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 30.

The spelling of 21421505244 in words is "twenty-one billion, four hundred twenty-one million, five hundred five thousand, two hundred forty-four".