21290448 has 20 divisors (see below), whose sum is σ = 55000448. Its totient is φ = 7096800.

The previous prime is 21290447. The next prime is 21290449. The reversal of 21290448 is 84409212.

It is an interprime number because it is at equal distance from previous prime (21290447) and next prime (21290449).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21290441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221728 + ... + 221823.

Almost surely, 2^21290448 is an apocalyptic number.

It is an amenable number.

21290448 is an abundant number, since it is smaller than the sum of its proper divisors (33710000).

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

21290448 is a wasteful number, since it uses less digits than its factorization.

21290448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 443562 (or 443556 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 21290448 is about 4614.1573445213. The cubic root of 21290448 is about 277.1585411365.

The spelling of 21290448 in words is "twenty-one million, two hundred ninety thousand, four hundred forty-eight".