221268181161557 has 16 divisors (see below), whose sum is σ = 229034675142000. Its totient is φ = 213510814454784.

The previous prime is 221268181161541. The next prime is 221268181161647. The reversal of 221268181161557 is 755161181862122.

It can be written as a sum of positive squares in 8 ways, for example, as 41724287600356 + 179543893561201 = 6459434^2 + 13399399^2 .

It is a cyclic number.

It is not a de Polignac number, because 221268181161557 - 2⁴ = 221268181161541 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 (221268181161257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 541544813 + ... + 541953245.

It is an arithmetic number, because the mean of its divisors is an integer number (14314667196375).

Almost surely, 2^{221268181161557} is an apocalyptic number.

It is an amenable number.

221268181161557 is a deficient number, since it is larger than the sum of its proper divisors (7766493980443).

221268181161557 is a wasteful number, since it uses less digits than its factorization.

221268181161557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419560.

The product of its digits is 3225600, while the sum is 56.

The spelling of 221268181161557 in words is "two hundred twenty-one trillion, two hundred sixty-eight billion, one hundred eighty-one million, one hundred sixty-one thousand, five hundred fifty-seven".