21004412 has 24 divisors (see below), whose sum is σ = 43185072. Its totient is φ = 8812800.

The previous prime is 21004387. The next prime is 21004447. The reversal of 21004412 is 21440012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17789 + ... + 18932.

It is an arithmetic number, because the mean of its divisors is an integer number (1799378).

Almost surely, 2^21004412 is an apocalyptic number.

21004412 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21004412 is an abundant number, since it is smaller than the sum of its proper divisors (22180660).

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

21004412 is a wasteful number, since it uses less digits than its factorization.

21004412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36749 (or 36747 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21004412 is about 4583.0570583400. The cubic root of 21004412 is about 275.9117375129.

Adding to 21004412 its reverse (21440012), we get a palindrome (42444424).

Subtracting 21004412 from its reverse (21440012), we obtain a square (435600 = 660²).

The spelling of 21004412 in words is "twenty-one million, four thousand, four hundred twelve".