21326490 has 80 divisors (see below), whose sum is σ = 58100328. Its totient is φ = 5612544.

The previous prime is 21326479. The next prime is 21326527. The reversal of 21326490 is 9462312.

21326490 is a `hidden beast` number, since 2 + 13 + 2 + 649 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 7241481 + 14085009 = 2691^2 + 3753^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 9.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 91414 + ... + 91646.

Almost surely, 2^21326490 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21326490, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29050164).

21326490 is an abundant number, since it is smaller than the sum of its proper divisors (36773838).

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

21326490 is a wasteful number, since it uses less digits than its factorization.

21326490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 365 (or 356 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 21326490 is about 4618.0612815336. The cubic root of 21326490 is about 277.3148509292.

The spelling of 21326490 in words is "twenty-one million, three hundred twenty-six thousand, four hundred ninety".