21079404 has 72 divisors (see below), whose sum is σ = 56194320. Its totient is φ = 6652800.

The previous prime is 21079393. The next prime is 21079459. The reversal of 21079404 is 40497012.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 63519 + ... + 63849.

Almost surely, 2^21079404 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21079404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28097160).

21079404 is an abundant number, since it is smaller than the sum of its proper divisors (35114916).

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

21079404 is a wasteful number, since it uses less digits than its factorization.

21079404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431 (or 426 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21079404 is about 4591.2312074214. The cubic root of 21079404 is about 276.2397098328.

It can be divided in two parts, 2107 and 9404, that added together give a palindrome (11511).

The spelling of 21079404 in words is "twenty-one million, seventy-nine thousand, four hundred four".