221660432057 has 4 divisors (see below), whose sum is σ = 221713809780. Its totient is φ = 221607054336.

The previous prime is 221660432039. The next prime is 221660432111. The reversal of 221660432057 is 750234066122.

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 23774247721 + 197886184336 = 154189^2 + 444844^2 .

It is a cyclic number.

It is not a de Polignac number, because 221660432057 - 2²⁸ = 221391996601 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221660432057.

It is not an unprimeable number, because it can be changed into a prime (221660432857) 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, 26682632 + ... + 26690937.

It is an arithmetic number, because the mean of its divisors is an integer number (55428452445).

Almost surely, 2^221660432057 is an apocalyptic number.

It is an amenable number.

221660432057 is a deficient number, since it is larger than the sum of its proper divisors (53377723).

221660432057 is an equidigital number, since it uses as much as digits as its factorization.

221660432057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53377722.

The product of its (nonzero) digits is 120960, while the sum is 38.

Adding to 221660432057 its reverse (750234066122), we get a palindrome (971894498179).

The spelling of 221660432057 in words is "two hundred twenty-one billion, six hundred sixty million, four hundred thirty-two thousand, fifty-seven".