21109007 has 2 divisors, whose sum is σ = 21109008. Its totient is φ = 21109006.

The previous prime is 21108977. The next prime is 21109061. The reversal of 21109007 is 70090112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21109007 - 2⁸ = 21108751 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21109007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21100007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10554503 + 10554504.

It is an arithmetic number, because the mean of its divisors is an integer number (10554504).

Almost surely, 2^21109007 is an apocalyptic number.

21109007 is a deficient number, since it is larger than the sum of its proper divisors (1).

21109007 is an equidigital number, since it uses as much as digits as its factorization.

21109007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 126, while the sum is 20.

The square root of 21109007 is about 4594.4539392620. The cubic root of 21109007 is about 276.3689623655.

Adding to 21109007 its reverse (70090112), we get a palindrome (91199119).

The spelling of 21109007 in words is "twenty-one million, one hundred nine thousand, seven".