21214204440 has 128 divisors (see below), whose sum is σ = 74769004800. Its totient is φ = 4747230720.

The previous prime is 21214204421. The next prime is 21214204441. The reversal of 21214204440 is 4440241212.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21214204440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21214204441) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 600970 + ... + 635289.

It is an arithmetic number, because the mean of its divisors is an integer number (584132850).

Almost surely, 2^21214204440 is an apocalyptic number.

21214204440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21214204440 is an abundant number, since it is smaller than the sum of its proper divisors (53554800360).

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

21214204440 is a wasteful number, since it uses less digits than its factorization.

21214204440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1236297 (or 1236293 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 24.

Adding to 21214204440 its reverse (4440241212), we get a palindrome (25654445652).

The spelling of 21214204440 in words is "twenty-one billion, two hundred fourteen million, two hundred four thousand, four hundred forty".