21621348 has 144 divisors (see below), whose sum is σ = 68140800. Its totient is φ = 5757696.

The previous prime is 21621337. The next prime is 21621371. The reversal of 21621348 is 84312612.

21621348 is a `hidden beast` number, since 2 + 1 + 621 + 34 + 8 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 209865 + ... + 209967.

It is an arithmetic number, because the mean of its divisors is an integer number (473200).

Almost surely, 2^21621348 is an apocalyptic number.

21621348 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21621348, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34070400).

21621348 is an abundant number, since it is smaller than the sum of its proper divisors (46519452).

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

21621348 is a wasteful number, since it uses less digits than its factorization.

21621348 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151 (or 132 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21621348 is about 4649.8761273823. The cubic root of 21621348 is about 278.5870485465.

The spelling of 21621348 in words is "twenty-one million, six hundred twenty-one thousand, three hundred forty-eight".