21226021540 has 12 divisors (see below), whose sum is σ = 44574645276. Its totient is φ = 8490408608.

The previous prime is 21226021507. The next prime is 21226021541. The reversal of 21226021540 is 4512062212.

It can be written as a sum of positive squares in 2 ways, for example, as 7783474176 + 13442547364 = 88224^2 + 115942^2 .

It is not an unprimeable number, because it can be changed into a prime (21226021541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 530650519 + ... + 530650558.

It is an arithmetic number, because the mean of its divisors is an integer number (3714553773).

Almost surely, 2^21226021540 is an apocalyptic number.

21226021540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21226021540 is an abundant number, since it is smaller than the sum of its proper divisors (23348623736).

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

21226021540 is a wasteful number, since it uses less digits than its factorization.

21226021540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061301086 (or 1061301084 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21226021540 its reverse (4512062212), we get a palindrome (25738083752).

The spelling of 21226021540 in words is "twenty-one billion, two hundred twenty-six million, twenty-one thousand, five hundred forty".