21091009245 has 32 divisors (see below), whose sum is σ = 34244235648. Its totient is φ = 11083358208.

The previous prime is 21091009243. The next prime is 21091009271. The reversal of 21091009245 is 54290019012.

It is not a de Polignac number, because 21091009245 - 2¹ = 21091009243 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21091009243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 298357 + ... + 362213.

It is an arithmetic number, because the mean of its divisors is an integer number (1070132364).

Almost surely, 2^21091009245 is an apocalyptic number.

It is an amenable number.

21091009245 is a deficient number, since it is larger than the sum of its proper divisors (13153226403).

21091009245 is a wasteful number, since it uses less digits than its factorization.

21091009245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64189.

The product of its (nonzero) digits is 6480, while the sum is 33.

The spelling of 21091009245 in words is "twenty-one billion, ninety-one million, nine thousand, two hundred forty-five".