21621468 has 96 divisors (see below), whose sum is σ = 59754240. Its totient is φ = 6013440.

The previous prime is 21621463. The next prime is 21621469. The reversal of 21621468 is 86412612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621463) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 92680 + ... + 92912.

It is an arithmetic number, because the mean of its divisors is an integer number (622440).

Almost surely, 2^21621468 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 21621468, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29877120).

21621468 is an abundant number, since it is smaller than the sum of its proper divisors (38132772).

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

21621468 is a wasteful number, since it uses less digits than its factorization.

21621468 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307 (or 305 counting only the distinct ones).

The product of its digits is 4608, while the sum is 30.

The square root of 21621468 is about 4649.8890309340. The cubic root of 21621468 is about 278.5875639381.

The spelling of 21621468 in words is "twenty-one million, six hundred twenty-one thousand, four hundred sixty-eight".