21273763 has 4 divisors (see below), whose sum is σ = 24312880. Its totient is φ = 18234648.

The previous prime is 21273761. The next prime is 21273803. The reversal of 21273763 is 36737212.

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 21273763 - 2¹ = 21273761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21273761) by changing a digit.

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, 1519548 + ... + 1519561.

It is an arithmetic number, because the mean of its divisors is an integer number (6078220).

Almost surely, 2^21273763 is an apocalyptic number.

21273763 is a deficient number, since it is larger than the sum of its proper divisors (3039117).

21273763 is an equidigital number, since it uses as much as digits as its factorization.

21273763 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3039116.

The product of its digits is 10584, while the sum is 31.

The square root of 21273763 is about 4612.3489677170. The cubic root of 21273763 is about 277.0861205717.

The spelling of 21273763 in words is "twenty-one million, two hundred seventy-three thousand, seven hundred sixty-three".