21672245 has 8 divisors (see below), whose sum is σ = 29721984. Its totient is φ = 14860944.

The previous prime is 21672239. The next prime is 21672271. The reversal of 21672245 is 54227612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21672245 - 2⁶ = 21672181 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 309569 + ... + 309638.

It is an arithmetic number, because the mean of its divisors is an integer number (3715248).

Almost surely, 2^21672245 is an apocalyptic number.

It is an amenable number.

21672245 is a deficient number, since it is larger than the sum of its proper divisors (8049739).

21672245 is an equidigital number, since it uses as much as digits as its factorization.

21672245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619219.

The product of its digits is 6720, while the sum is 29.

The square root of 21672245 is about 4655.3458518138. The cubic root of 21672245 is about 278.8054767019.

Adding to 21672245 its reverse (54227612), we get a palindrome (75899857).

The spelling of 21672245 in words is "twenty-one million, six hundred seventy-two thousand, two hundred forty-five".