21221365046065 has 32 divisors (see below), whose sum is σ = 27997090452000. Its totient is φ = 15370107260928.

The previous prime is 21221365046053. The next prime is 21221365046107. The reversal of 21221365046065 is 56064056312212.

It can be written as a sum of positive squares in 16 ways, for example, as 853907213041 + 20367457833024 = 924071^2 + 4513032^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221365046065 - 2¹¹ = 21221365044017 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15338910 + ... + 16665079.

It is an arithmetic number, because the mean of its divisors is an integer number (874909076625).

Almost surely, 2^{21221365046065} is an apocalyptic number.

It is an amenable number.

21221365046065 is a deficient number, since it is larger than the sum of its proper divisors (6775725405935).

21221365046065 is a wasteful number, since it uses less digits than its factorization.

21221365046065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32004309.

The product of its (nonzero) digits is 518400, while the sum is 43.

The spelling of 21221365046065 in words is "twenty-one trillion, two hundred twenty-one billion, three hundred sixty-five million, forty-six thousand, sixty-five".