21872107 has 2 divisors, whose sum is σ = 21872108. Its totient is φ = 21872106.

The previous prime is 21872087. The next prime is 21872113. The reversal of 21872107 is 70127812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21872107 - 2¹⁹ = 21347819 is a 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 (21872407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10936053 + 10936054.

It is an arithmetic number, because the mean of its divisors is an integer number (10936054).

Almost surely, 2^21872107 is an apocalyptic number.

21872107 is a deficient number, since it is larger than the sum of its proper divisors (1).

21872107 is an equidigital number, since it uses as much as digits as its factorization.

21872107 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 21872107 is about 4676.7624485321. The cubic root of 21872107 is about 279.6599059592.

Adding to 21872107 its reverse (70127812), we get a palindrome (91999919).

The spelling of 21872107 in words is "twenty-one million, eight hundred seventy-two thousand, one hundred seven".