21291450 has 48 divisors (see below), whose sum is σ = 54047136. Its totient is φ = 5544000.

The previous prime is 21291449. The next prime is 21291467. The reversal of 21291450 is 5419212.

It is a hoax number, since the sum of its digits (24) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21291450.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4800 + ... + 8100.

It is an arithmetic number, because the mean of its divisors is an integer number (1125982).

Almost surely, 2^21291450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21291450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27023568).

21291450 is an abundant number, since it is smaller than the sum of its proper divisors (32755686).

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

21291450 is a wasteful number, since it uses less digits than its factorization.

21291450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3359 (or 3354 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 21291450 is about 4614.2659221159. The cubic root of 21291450 is about 277.1628890723.

The spelling of 21291450 in words is "twenty-one million, two hundred ninety-one thousand, four hundred fifty".