21620352 has 128 divisors (see below), whose sum is σ = 63745920. Its totient is φ = 6451200.

The previous prime is 21620323. The next prime is 21620359. The reversal of 21620352 is 25302612.

It is a tau number, because it is divible by the number of its divisors (128).

It is a zygodrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21620359) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 304477 + ... + 304547.

It is an arithmetic number, because the mean of its divisors is an integer number (498015).

Almost surely, 2^21620352 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 21620352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31872960).

21620352 is an abundant number, since it is smaller than the sum of its proper divisors (42125568).

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

21620352 is a wasteful number, since it uses less digits than its factorization.

21620352 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21620352 is about 4649.7690265216. The cubic root of 21620352 is about 278.5827707226.

Adding to 21620352 its reverse (25302612), we get a palindrome (46922964).

The spelling of 21620352 in words is "twenty-one million, six hundred twenty thousand, three hundred fifty-two".