21672107 has 2 divisors, whose sum is σ = 21672108. Its totient is φ = 21672106.

The previous prime is 21672097. The next prime is 21672109. The reversal of 21672107 is 70127612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21672107 - 2⁸ = 21671851 is a prime.

Together with 21672109, it forms a pair of twin primes.

It is a Chen prime.

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

It is not a weakly prime, because it can be changed into another prime (21672109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10836053 + 10836054.

It is an arithmetic number, because the mean of its divisors is an integer number (10836054).

Almost surely, 2^21672107 is an apocalyptic number.

21672107 is a deficient number, since it is larger than the sum of its proper divisors (1).

21672107 is an equidigital number, since it uses as much as digits as its factorization.

21672107 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1176, while the sum is 26.

The square root of 21672107 is about 4655.3310301202. The cubic root of 21672107 is about 278.8048849275.

Adding to 21672107 its reverse (70127612), we get a palindrome (91799719).

The spelling of 21672107 in words is "twenty-one million, six hundred seventy-two thousand, one hundred seven".