21672365 has 32 divisors (see below), whose sum is σ = 32368896. Its totient is φ = 13685760.

The previous prime is 21672359. The next prime is 21672373. The reversal of 21672365 is 56327612.

It is not a de Polignac number, because 21672365 - 2⁴ = 21672349 is a prime.

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

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11264 + ... + 13046.

It is an arithmetic number, because the mean of its divisors is an integer number (1011528).

Almost surely, 2^21672365 is an apocalyptic number.

It is an amenable number.

21672365 is a deficient number, since it is larger than the sum of its proper divisors (10696531).

21672365 is a wasteful number, since it uses less digits than its factorization.

21672365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1829.

The product of its digits is 15120, while the sum is 32.

The square root of 21672365 is about 4655.3587402047. The cubic root of 21672365 is about 278.8059912863.

Adding to 21672365 its reverse (56327612), we get a palindrome (77999977).

The spelling of 21672365 in words is "twenty-one million, six hundred seventy-two thousand, three hundred sixty-five".