221661742397 has 8 divisors (see below), whose sum is σ = 228840076800. Its totient is φ = 214485155280.

The previous prime is 221661742387. The next prime is 221661742399. The reversal of 221661742397 is 793247166122.

221661742397 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221661742397 - 2¹⁸ = 221661480253 is a prime.

It is a super-3 number, since 3×221661742397³ (a number of 35 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221661742399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 176522 + ... + 688827.

It is an arithmetic number, because the mean of its divisors is an integer number (28605009600).

Almost surely, 2^221661742397 is an apocalyptic number.

It is an amenable number.

221661742397 is a deficient number, since it is larger than the sum of its proper divisors (7178334403).

221661742397 is an equidigital number, since it uses as much as digits as its factorization.

221661742397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 873643.

The product of its digits is 1524096, while the sum is 50.

The spelling of 221661742397 in words is "two hundred twenty-one billion, six hundred sixty-one million, seven hundred forty-two thousand, three hundred ninety-seven".