21240718085 has 16 divisors (see below), whose sum is σ = 27011071296. Its totient is φ = 15979461888.

The previous prime is 21240718049. The next prime is 21240718091. The reversal of 21240718085 is 58081704212.

It is a cyclic number.

It is not a de Polignac number, because 21240718085 - 2⁶ = 21240718021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4367 + ... + 206156.

It is an arithmetic number, because the mean of its divisors is an integer number (1688191956).

Almost surely, 2^21240718085 is an apocalyptic number.

It is an amenable number.

21240718085 is a deficient number, since it is larger than the sum of its proper divisors (5770353211).

21240718085 is a wasteful number, since it uses less digits than its factorization.

21240718085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211732.

The product of its (nonzero) digits is 35840, while the sum is 38.

The spelling of 21240718085 in words is "twenty-one billion, two hundred forty million, seven hundred eighteen thousand, eighty-five".