21672953 has 4 divisors (see below), whose sum is σ = 21684048. Its totient is φ = 21661860.

The previous prime is 21672913. The next prime is 21672967. The reversal of 21672953 is 35927612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21672953 - 2¹⁰ = 21671929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21672913) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1751 + ... + 6812.

It is an arithmetic number, because the mean of its divisors is an integer number (5421012).

Almost surely, 2^21672953 is an apocalyptic number.

It is an amenable number.

21672953 is a deficient number, since it is larger than the sum of its proper divisors (11095).

21672953 is an equidigital number, since it uses as much as digits as its factorization.

21672953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11094.

The product of its digits is 22680, while the sum is 35.

The square root of 21672953 is about 4655.4218928041. The cubic root of 21672953 is about 278.8085127222.

The spelling of 21672953 in words is "twenty-one million, six hundred seventy-two thousand, nine hundred fifty-three".