21145263 has 24 divisors (see below), whose sum is σ = 31019280. Its totient is φ = 12810112.

The previous prime is 21145261. The next prime is 21145301. The reversal of 21145263 is 36254112.

It is not a de Polignac number, because 21145263 - 2¹ = 21145261 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 729133 + ... + 729161.

It is an arithmetic number, because the mean of its divisors is an integer number (1292470).

Almost surely, 2^21145263 is an apocalyptic number.

21145263 is a deficient number, since it is larger than the sum of its proper divisors (9874017).

21145263 is an frugal number, since it uses more digits than its factorization.

21145263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124 (or 49 counting only the distinct ones).

The product of its digits is 1440, while the sum is 24.

The square root of 21145263 is about 4598.3978731728. The cubic root of 21145263 is about 276.5270986829.

Adding to 21145263 its reverse (36254112), we get a palindrome (57399375).

The spelling of 21145263 in words is "twenty-one million, one hundred forty-five thousand, two hundred sixty-three".