21446490 has 64 divisors (see below), whose sum is σ = 55996416. Its totient is φ = 5225472.

The previous prime is 21446489. The next prime is 21446501. The reversal of 21446490 is 9464412.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

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, 49314 + ... + 49746.

It is an arithmetic number, because the mean of its divisors is an integer number (874944).

Almost surely, 2^21446490 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21446490, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27998208).

21446490 is an abundant number, since it is smaller than the sum of its proper divisors (34549926).

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

21446490 is a wasteful number, since it uses less digits than its factorization.

21446490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 583.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 21446490 is about 4631.0355213494. The cubic root of 21446490 is about 277.8340106007.

The spelling of 21446490 in words is "twenty-one million, four hundred forty-six thousand, four hundred ninety".