21213250 has 32 divisors (see below), whose sum is σ = 40485744. Its totient is φ = 8320000.

The previous prime is 21213193. The next prime is 21213251. The reversal of 21213250 is 5231212.

It can be written as a sum of positive squares in 8 ways, for example, as 8014561 + 13198689 = 2831^2 + 3633^2 .

It is not an unprimeable number, because it can be changed into a prime (21213251) 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, 12450 + ... + 14050.

Almost surely, 2^21213250 is an apocalyptic number.

21213250 is a deficient number, since it is larger than the sum of its proper divisors (19272494).

21213250 is a wasteful number, since it uses less digits than its factorization.

21213250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1671 (or 1661 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21213250 is about 4605.7844065913. The cubic root of 21213250 is about 276.8231482000.

Adding to 21213250 its reverse (5231212), we get a palindrome (26444462).

The spelling of 21213250 in words is "twenty-one million, two hundred thirteen thousand, two hundred fifty".