21141765 has 24 divisors (see below), whose sum is σ = 37271520. Its totient is φ = 11083104.

The previous prime is 21141751. The next prime is 21141779. The reversal of 21141765 is 56714112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21141751) and next prime (21141779).

It is not a de Polignac number, because 21141765 - 2⁵ = 21141733 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1327 + ... + 6636.

It is an arithmetic number, because the mean of its divisors is an integer number (1552980).

Almost surely, 2^21141765 is an apocalyptic number.

21141765 is the 2655-th octagonal number.

It is an amenable number.

21141765 is a deficient number, since it is larger than the sum of its proper divisors (16129755).

21141765 is a wasteful number, since it uses less digits than its factorization.

21141765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8033 (or 8030 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 21141765 is about 4598.0175075787. The cubic root of 21141765 is about 276.5118494813.

Adding to 21141765 its reverse (56714112), we get a palindrome (77855877).

The spelling of 21141765 in words is "twenty-one million, one hundred forty-one thousand, seven hundred sixty-five".