21239763 has 8 divisors (see below), whose sum is σ = 29010576. Its totient is φ = 13814400.

The previous prime is 21239759. The next prime is 21239797. The reversal of 21239763 is 36793212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21239763 - 2² = 21239759 is a prime.

It is a super-2 number, since 2×21239763² = 902255064592338, which contains 22 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21239753) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86218 + ... + 86463.

It is an arithmetic number, because the mean of its divisors is an integer number (3626322).

Almost surely, 2^21239763 is an apocalyptic number.

21239763 is a deficient number, since it is larger than the sum of its proper divisors (7770813).

21239763 is a wasteful number, since it uses less digits than its factorization.

21239763 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172725.

The product of its digits is 13608, while the sum is 33.

The square root of 21239763 is about 4608.6617363395. The cubic root of 21239763 is about 276.9384276687.

The spelling of 21239763 in words is "twenty-one million, two hundred thirty-nine thousand, seven hundred sixty-three".