21251036 has 12 divisors (see below), whose sum is σ = 37322712. Its totient is φ = 10587408.

The previous prime is 21251023. The next prime is 21251053. The reversal of 21251036 is 63015212.

It is a junction number, because it is equal to n+sod(n) for n = 21250999 and 21251017.

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 3 ways as a sum of consecutive naturals, for example, 8255 + ... + 10518.

It is an arithmetic number, because the mean of its divisors is an integer number (3110226).

Almost surely, 2^21251036 is an apocalyptic number.

It is an amenable number.

21251036 is a deficient number, since it is larger than the sum of its proper divisors (16071676).

21251036 is a wasteful number, since it uses less digits than its factorization.

21251036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19060 (or 19058 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21251036 is about 4609.8845972540. The cubic root of 21251036 is about 276.9874140085.

Adding to 21251036 its reverse (63015212), we get a palindrome (84266248).

The spelling of 21251036 in words is "twenty-one million, two hundred fifty-one thousand, thirty-six".