21220001440 has 96 divisors (see below), whose sum is σ = 54740193984. Its totient is φ = 7709245440.

The previous prime is 21220001431. The next prime is 21220001479. The reversal of 21220001440 is 4410002212.

It is a super-2 number, since 2×21220001440² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2136967 + ... + 2146873.

It is an arithmetic number, because the mean of its divisors is an integer number (570210354).

Almost surely, 2^21220001440 is an apocalyptic number.

21220001440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21220001440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27370096992).

21220001440 is an abundant number, since it is smaller than the sum of its proper divisors (33520192544).

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

21220001440 is a wasteful number, since it uses less digits than its factorization.

21220001440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11150 (or 11142 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21220001440 its reverse (4410002212), we get a palindrome (25630003652).

The spelling of 21220001440 in words is "twenty-one billion, two hundred twenty million, one thousand, four hundred forty".