21253030 has 16 divisors (see below), whose sum is σ = 38405664. Its totient is φ = 8467840.

The previous prime is 21253021. The next prime is 21253033. The reversal of 21253030 is 3035212.

It is a junction number, because it is equal to n+sod(n) for n = 21252995 and 21253013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1411 + ... + 6670.

It is an arithmetic number, because the mean of its divisors is an integer number (2400354).

Almost surely, 2^21253030 is an apocalyptic number.

21253030 is a deficient number, since it is larger than the sum of its proper divisors (17152634).

21253030 is a wasteful number, since it uses less digits than its factorization.

21253030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8351.

The product of its (nonzero) digits is 180, while the sum is 16.

The square root of 21253030 is about 4610.1008665755. The cubic root of 21253030 is about 276.9960770470.

Adding to 21253030 its reverse (3035212), we get a palindrome (24288242).

The spelling of 21253030 in words is "twenty-one million, two hundred fifty-three thousand, thirty".