21444502440 has 64 divisors (see below), whose sum is σ = 68117837760. Its totient is φ = 5382149120.

The previous prime is 21444502421. The next prime is 21444502447. The reversal of 21444502440 is 4420544412.

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

It is a junction number, because it is equal to n+sod(n) for n = 21444502398 and 21444502407.

It is not an unprimeable number, because it can be changed into a prime (21444502447) by changing a digit.

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, 5253966 + ... + 5258045.

It is an arithmetic number, because the mean of its divisors is an integer number (1064341215).

Almost surely, 2^21444502440 is an apocalyptic number.

21444502440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21444502440 is an abundant number, since it is smaller than the sum of its proper divisors (46673335320).

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

21444502440 is a wasteful number, since it uses less digits than its factorization.

21444502440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10512042 (or 10512038 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 30.

The spelling of 21444502440 in words is "twenty-one billion, four hundred forty-four million, five hundred two thousand, four hundred forty".