21251030 has 32 divisors (see below), whose sum is σ = 39736224. Its totient is φ = 8176896.

The previous prime is 21251023. The next prime is 21251053. The reversal of 21251030 is 3015212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21250996 and 21251014.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 31052 + ... + 31728.

It is an arithmetic number, because the mean of its divisors is an integer number (1241757).

Almost surely, 2^21251030 is an apocalyptic number.

21251030 is a deficient number, since it is larger than the sum of its proper divisors (18485194).

21251030 is a wasteful number, since it uses less digits than its factorization.

21251030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 800.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 21251030 is about 4609.8839464785. The cubic root of 21251030 is about 276.9873879403.

Adding to 21251030 its reverse (3015212), we get a palindrome (24266242).

The spelling of 21251030 in words is "twenty-one million, two hundred fifty-one thousand, thirty".