21036761 has 8 divisors (see below), whose sum is σ = 21689184. Its totient is φ = 20391840.

The previous prime is 21036751. The next prime is 21036767. The reversal of 21036761 is 16763012.

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 21036761 - 2¹⁰ = 21035737 is a prime.

It is a super-2 number, since 2×21036761² = 885090626742242, which contains 22 as substring.

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

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21036761.

It is not an unprimeable number, because it can be changed into a prime (21036767) 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, 4106 + ... + 7676.

It is an arithmetic number, because the mean of its divisors is an integer number (2711148).

Almost surely, 2^21036761 is an apocalyptic number.

It is an amenable number.

21036761 is a deficient number, since it is larger than the sum of its proper divisors (652423).

21036761 is a wasteful number, since it uses less digits than its factorization.

21036761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3751.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21036761 is about 4586.5848951044. The cubic root of 21036761 is about 276.0533092084.

Adding to 21036761 its reverse (16763012), we get a palindrome (37799773).

The spelling of 21036761 in words is "twenty-one million, thirty-six thousand, seven hundred sixty-one".