21221040040 has 64 divisors (see below), whose sum is σ = 48444076800. Its totient is φ = 8364964608.

The previous prime is 21221040031. The next prime is 21221040079. The reversal of 21221040040 is 4004012212.

It is a junction number, because it is equal to n+sod(n) for n = 21221039996 and 21221040023.

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, 1722382 + ... + 1734658.

It is an arithmetic number, because the mean of its divisors is an integer number (756938700).

Almost surely, 2^21221040040 is an apocalyptic number.

21221040040 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 21221040040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24222038400).

21221040040 is an abundant number, since it is smaller than the sum of its proper divisors (27223036760).

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

21221040040 is a wasteful number, since it uses less digits than its factorization.

21221040040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12914 (or 12910 counting only the distinct ones).

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

Adding to 21221040040 its reverse (4004012212), we get a palindrome (25225052252).

The spelling of 21221040040 in words is "twenty-one billion, two hundred twenty-one million, forty thousand, forty".