21211444420 has 12 divisors (see below), whose sum is σ = 44544033324. Its totient is φ = 8484577760.

The previous prime is 21211444411. The next prime is 21211444483. The reversal of 21211444420 is 2444411212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 11073773824 + 10137670596 = 105232^2 + 100686^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 530286091 + ... + 530286130.

It is an arithmetic number, because the mean of its divisors is an integer number (3712002777).

Almost surely, 2^21211444420 is an apocalyptic number.

21211444420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211444420 is an abundant number, since it is smaller than the sum of its proper divisors (23332588904).

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

21211444420 is a wasteful number, since it uses less digits than its factorization.

21211444420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1060572230 (or 1060572228 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 25.

Adding to 21211444420 its reverse (2444411212), we get a palindrome (23655855632).

The spelling of 21211444420 in words is "twenty-one billion, two hundred eleven million, four hundred forty-four thousand, four hundred twenty".