21778250 has 32 divisors (see below), whose sum is σ = 43911504. Its totient is φ = 8040000.

The previous prime is 21778223. The next prime is 21778259. The reversal of 21778250 is 5287712.

It can be written as a sum of positive squares in 8 ways, for example, as 90601 + 21687649 = 301^2 + 4657^2 .

It is not an unprimeable number, because it can be changed into a prime (21778259) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 101 + ... + 6600.

Almost surely, 2^21778250 is an apocalyptic number.

21778250 is an abundant number, since it is smaller than the sum of its proper divisors (22133254).

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

21778250 is a wasteful number, since it uses less digits than its factorization.

21778250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6731 (or 6721 counting only the distinct ones).

The product of its (nonzero) digits is 7840, while the sum is 32.

The square root of 21778250 is about 4666.7172616305. The cubic root of 21778250 is about 279.2593093680.

The spelling of 21778250 in words is "twenty-one million, seven hundred seventy-eight thousand, two hundred fifty".