21021440404 has 12 divisors (see below), whose sum is σ = 36789996628. Its totient is φ = 10510012800.

The previous prime is 21021440371. The next prime is 21021440413. The reversal of 21021440404 is 40404412012.

It can be written as a sum of positive squares in 2 ways, for example, as 17029728004 + 3991712400 = 130498^2 + 63180^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106917 + ... + 231244.

Almost surely, 2^21021440404 is an apocalyptic number.

It is an amenable number.

21021440404 is a deficient number, since it is larger than the sum of its proper divisors (15768556224).

21021440404 is a wasteful number, since it uses less digits than its factorization.

21021440404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 353706 (or 353704 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 22.

Adding to 21021440404 its reverse (40404412012), we get a palindrome (61425852416).

The spelling of 21021440404 in words is "twenty-one billion, twenty-one million, four hundred forty thousand, four hundred four".