21106907 has 2 divisors, whose sum is σ = 21106908. Its totient is φ = 21106906.

The previous prime is 21106873. The next prime is 21106933. The reversal of 21106907 is 70960112.

It is an a-pointer prime, because the next prime (21106933) can be obtained adding 21106907 to its sum of digits (26).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21106907 - 2¹⁸ = 20844763 is a prime.

It is not a weakly prime, because it can be changed into another prime (21106957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10553453 + 10553454.

It is an arithmetic number, because the mean of its divisors is an integer number (10553454).

Almost surely, 2^21106907 is an apocalyptic number.

21106907 is a deficient number, since it is larger than the sum of its proper divisors (1).

21106907 is an equidigital number, since it uses as much as digits as its factorization.

21106907 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 21106907 is about 4594.2253971698. The cubic root of 21106907 is about 276.3597973352.

The spelling of 21106907 in words is "twenty-one million, one hundred six thousand, nine hundred seven".