21050765 has 8 divisors (see below), whose sum is σ = 26590560. Its totient is φ = 15954192.

The previous prime is 21050749. The next prime is 21050801. The reversal of 21050765 is 56705012.

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 21050765 - 2⁴ = 21050749 is a prime.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 110699 + ... + 110888.

It is an arithmetic number, because the mean of its divisors is an integer number (3323820).

Almost surely, 2^21050765 is an apocalyptic number.

It is an amenable number.

21050765 is a deficient number, since it is larger than the sum of its proper divisors (5539795).

21050765 is a wasteful number, since it uses less digits than its factorization.

21050765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221611.

The product of its (nonzero) digits is 2100, while the sum is 26.

The square root of 21050765 is about 4588.1112671774. Note that the first 3 decimals coincide. The cubic root of 21050765 is about 276.1145510989.

Adding to 21050765 its reverse (56705012), we get a palindrome (77755777).

The spelling of 21050765 in words is "twenty-one million, fifty thousand, seven hundred sixty-five".