221721780493 has 4 divisors (see below), whose sum is σ = 221864552028. Its totient is φ = 221579008960.

The previous prime is 221721780491. The next prime is 221721780551. The reversal of 221721780493 is 394087127122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 95553319689 + 126168460804 = 309117^2 + 355202^2 .

It is a cyclic number.

It is not a de Polignac number, because 221721780493 - 2¹ = 221721780491 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221721780491) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71383438 + ... + 71386543.

It is an arithmetic number, because the mean of its divisors is an integer number (55466138007).

Almost surely, 2^221721780493 is an apocalyptic number.

It is an amenable number.

221721780493 is a deficient number, since it is larger than the sum of its proper divisors (142771535).

221721780493 is a wasteful number, since it uses less digits than its factorization.

221721780493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142771534.

The product of its (nonzero) digits is 338688, while the sum is 46.

The spelling of 221721780493 in words is "two hundred twenty-one billion, seven hundred twenty-one million, seven hundred eighty thousand, four hundred ninety-three".