21369672 has 24 divisors (see below), whose sum is σ = 57876390. Its totient is φ = 7123200.

The previous prime is 21369659. The next prime is 21369679. The reversal of 21369672 is 27696312.

It can be written as a sum of positive squares in only one way, i.e., 19766916 + 1602756 = 4446^2 + 1266^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21369679) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 148329 + ... + 148472.

Almost surely, 2^21369672 is an apocalyptic number.

It is an amenable number.

21369672 is an abundant number, since it is smaller than the sum of its proper divisors (36506718).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21369672 is a wasteful number, since it uses less digits than its factorization.

21369672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296813 (or 296806 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 21369672 is about 4622.7342558274. The cubic root of 21369672 is about 277.5018943138.

The spelling of 21369672 in words is "twenty-one million, three hundred sixty-nine thousand, six hundred seventy-two".