21252270 has 32 divisors (see below), whose sum is σ = 54929952. Its totient is φ = 5231232.

The previous prime is 21252269. The next prime is 21252281. The reversal of 21252270 is 7225212.

It is a happy number.

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26857 + ... + 27636.

It is an arithmetic number, because the mean of its divisors is an integer number (1716561).

Almost surely, 2^21252270 is an apocalyptic number.

21252270 is an abundant number, since it is smaller than the sum of its proper divisors (33677682).

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

21252270 is a wasteful number, since it uses less digits than its factorization.

21252270 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54516.

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 21252270 is about 4610.0184381410. The cubic root of 21252270 is about 276.9927752507.

Adding to 21252270 its reverse (7225212), we get a palindrome (28477482).

The spelling of 21252270 in words is "twenty-one million, two hundred fifty-two thousand, two hundred seventy".