21131063 has 4 divisors (see below), whose sum is σ = 21446520. Its totient is φ = 20815608.

The previous prime is 21131041. The next prime is 21131069. The reversal of 21131063 is 36013112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21131063 - 2¹² = 21126967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131069) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 157628 + ... + 157761.

It is an arithmetic number, because the mean of its divisors is an integer number (5361630).

Almost surely, 2^21131063 is an apocalyptic number.

21131063 is a deficient number, since it is larger than the sum of its proper divisors (315457).

21131063 is an equidigital number, since it uses as much as digits as its factorization.

21131063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315456.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 21131063 is about 4596.8535978428. The cubic root of 21131063 is about 276.4651846723.

Adding to 21131063 its reverse (36013112), we get a palindrome (57144175).

The spelling of 21131063 in words is "twenty-one million, one hundred thirty-one thousand, sixty-three".