21440442720 has 48 divisors (see below), whose sum is σ = 67537396080. Its totient is φ = 5717451264.

The previous prime is 21440442713. The next prime is 21440442733. The reversal of 21440442720 is 2724404412.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22333315 + ... + 22334274.

It is an arithmetic number, because the mean of its divisors is an integer number (1407029085).

Almost surely, 2^21440442720 is an apocalyptic number.

21440442720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21440442720 is an abundant number, since it is smaller than the sum of its proper divisors (46096953360).

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

21440442720 is a wasteful number, since it uses less digits than its factorization.

21440442720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44667607 (or 44667599 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 30.

The spelling of 21440442720 in words is "twenty-one billion, four hundred forty million, four hundred forty-two thousand, seven hundred twenty".