21812763 has 16 divisors (see below), whose sum is σ = 34684416. Its totient is φ = 11922240.

The previous prime is 21812759. The next prime is 21812783. The reversal of 21812763 is 36721812.

It is not a de Polignac number, because 21812763 - 2² = 21812759 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 21812763.

It is not an unprimeable number, because it can be changed into a prime (21812723) 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 15 ways as a sum of consecutive naturals, for example, 22098 + ... + 23063.

It is an arithmetic number, because the mean of its divisors is an integer number (2167776).

Almost surely, 2^21812763 is an apocalyptic number.

21812763 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21812763 is a deficient number, since it is larger than the sum of its proper divisors (12871653).

21812763 is a wasteful number, since it uses less digits than its factorization.

21812763 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45194.

The product of its digits is 4032, while the sum is 30.

The square root of 21812763 is about 4670.4135791170. The cubic root of 21812763 is about 279.4067498912.

The spelling of 21812763 in words is "twenty-one million, eight hundred twelve thousand, seven hundred sixty-three".