21231036 has 18 divisors (see below), whose sum is σ = 53667432. Its totient is φ = 7077000.

The previous prime is 21231029. The next prime is 21231107. The reversal of 21231036 is 63013212.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 294840 + ... + 294911.

It is an arithmetic number, because the mean of its divisors is an integer number (2981524).

Almost surely, 2^21231036 is an apocalyptic number.

It is an amenable number.

21231036 is an abundant number, since it is smaller than the sum of its proper divisors (32436396).

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

21231036 is a wasteful number, since it uses less digits than its factorization.

21231036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 589761 (or 589756 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21231036 is about 4607.7148349263. The cubic root of 21231036 is about 276.9004929588.

Adding to 21231036 its reverse (63013212), we get a palindrome (84244248).

The spelling of 21231036 in words is "twenty-one million, two hundred thirty-one thousand, thirty-six".