21326370 has 64 divisors (see below), whose sum is σ = 55641600. Its totient is φ = 5200128.

The previous prime is 21326363. The next prime is 21326387. The reversal of 21326370 is 7362312.

It is a self number, because there is not a number n which added to its sum of digits gives 21326370.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 57927 + ... + 58293.

It is an arithmetic number, because the mean of its divisors is an integer number (869400).

Almost surely, 2^21326370 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21326370, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27820800).

21326370 is an abundant number, since it is smaller than the sum of its proper divisors (34315230).

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

21326370 is a wasteful number, since it uses less digits than its factorization.

21326370 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 539.

The product of its (nonzero) digits is 1512, while the sum is 24.

The square root of 21326370 is about 4618.0482890503. The cubic root of 21326370 is about 277.3143307960.

Adding to 21326370 its reverse (7362312), we get a palindrome (28688682).

The spelling of 21326370 in words is "twenty-one million, three hundred twenty-six thousand, three hundred seventy".