21032404 has 12 divisors (see below), whose sum is σ = 36839124. Its totient is φ = 10506944.

The previous prime is 21032399. The next prime is 21032437. The reversal of 21032404 is 40423012.

It can be written as a sum of positive squares in 2 ways, for example, as 1690000 + 19342404 = 1300^2 + 4398^2 .

It is a congruent number.

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, 6672 + ... + 9304.

It is an arithmetic number, because the mean of its divisors is an integer number (3069927).

Almost surely, 2^21032404 is an apocalyptic number.

It is an amenable number.

21032404 is a deficient number, since it is larger than the sum of its proper divisors (15806720).

21032404 is a wasteful number, since it uses less digits than its factorization.

21032404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4634 (or 4632 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21032404 is about 4586.1098983779. The cubic root of 21032404 is about 276.0342497579.

Adding to 21032404 its reverse (40423012), we get a palindrome (61455416).

The spelling of 21032404 in words is "twenty-one million, thirty-two thousand, four hundred four".