220791693801721 has 9 divisors (see below), whose sum is σ = 256839438274821. Its totient is φ = 189249934104252.

The previous prime is 220791693801719. The next prime is 220791693801739. The reversal of 220791693801721 is 127108396197022.

The square root of 220791693801721 is 14859061.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 220791693801721 - 2¹ = 220791693801719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (220791693801121) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 102952066 + ... + 105074788.

It is an arithmetic number, because the mean of its divisors is an integer number (28537715363869).

Almost surely, 2^{220791693801721} is an apocalyptic number.

220791693801721 is the 14859061-st square number.

220791693801721 is the 7429531-st centered octagonal number.

It is an amenable number.

220791693801721 is a deficient number, since it is larger than the sum of its proper divisors (36047744473100).

220791693801721 is an frugal number, since it uses more digits than its factorization.

220791693801721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4245460 (or 2122730 counting only the distinct ones).

The product of its (nonzero) digits is 4572288, while the sum is 58.

The spelling of 220791693801721 in words is "two hundred twenty trillion, seven hundred ninety-one billion, six hundred ninety-three million, eight hundred one thousand, seven hundred twenty-one".