21427404 has 48 divisors (see below), whose sum is σ = 52550400. Its totient is φ = 6785856.

The previous prime is 21427381. The next prime is 21427447. The reversal of 21427404 is 40472412.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22857 + ... + 23775.

It is an arithmetic number, because the mean of its divisors is an integer number (1094800).

Almost surely, 2^21427404 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 21427404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26275200).

21427404 is an abundant number, since it is smaller than the sum of its proper divisors (31122996).

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

21427404 is a wasteful number, since it uses less digits than its factorization.

21427404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1022 (or 1020 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 24.

The square root of 21427404 is about 4628.9744004477. The cubic root of 21427404 is about 277.7515679922.

Adding to 21427404 its reverse (40472412), we get a palindrome (61899816).

The spelling of 21427404 in words is "twenty-one million, four hundred twenty-seven thousand, four hundred four".