21332421 has 36 divisors (see below), whose sum is σ = 35686560. Its totient is φ = 12236400.

The previous prime is 21332419. The next prime is 21332471. The reversal of 21332421 is 12423312.

21332421 is a `hidden beast` number, since 213 + 32 + 421 = 666.

It is not a de Polignac number, because 21332421 - 2¹ = 21332419 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21332394 and 21332403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21332401) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 20176 + ... + 21206.

Almost surely, 2^21332421 is an apocalyptic number.

It is an amenable number.

21332421 is a deficient number, since it is larger than the sum of its proper divisors (14354139).

21332421 is a wasteful number, since it uses less digits than its factorization.

21332421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1078 (or 1064 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 21332421 is about 4618.7033894806. The cubic root of 21332421 is about 277.3405560801.

Adding to 21332421 its reverse (12423312), we get a palindrome (33755733).

It can be divided in two parts, 2133 and 2421, that added together give a palindrome (4554).

The spelling of 21332421 in words is "twenty-one million, three hundred thirty-two thousand, four hundred twenty-one".