21020763 has 8 divisors (see below), whose sum is σ = 28059408. Its totient is φ = 13997984.

The previous prime is 21020761. The next prime is 21020777. The reversal of 21020763 is 36702012.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21020763 - 2¹ = 21020761 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21020761) 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, 420 + ... + 6497.

It is an arithmetic number, because the mean of its divisors is an integer number (3507426).

Almost surely, 2^21020763 is an apocalyptic number.

21020763 is a deficient number, since it is larger than the sum of its proper divisors (7038645).

21020763 is a wasteful number, since it uses less digits than its factorization.

21020763 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7933.

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 21020763 is about 4584.8405642945. The cubic root of 21020763 is about 275.9833139461.

Adding to 21020763 its reverse (36702012), we get a palindrome (57722775).

The spelling of 21020763 in words is "twenty-one million, twenty thousand, seven hundred sixty-three".