21404124404 has 24 divisors (see below), whose sum is σ = 40362313320. Its totient is φ = 9873005184.

The previous prime is 21404124403. The next prime is 21404124421. The reversal of 21404124404 is 40442140412.

It can be written as a sum of positive squares in 4 ways, for example, as 1522560400 + 19881564004 = 39020^2 + 141002^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21404124403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31559 + ... + 209294.

It is an arithmetic number, because the mean of its divisors is an integer number (1681763055).

Almost surely, 2^21404124404 is an apocalyptic number.

It is an amenable number.

21404124404 is a deficient number, since it is larger than the sum of its proper divisors (18958188916).

21404124404 is a wasteful number, since it uses less digits than its factorization.

21404124404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242579 (or 242577 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 26.

Adding to 21404124404 its reverse (40442140412), we get a palindrome (61846264816).

The spelling of 21404124404 in words is "twenty-one billion, four hundred four million, one hundred twenty-four thousand, four hundred four".