221600661667 has 64 divisors (see below), whose sum is σ = 291207168000. Its totient is φ = 168450004800.

The previous prime is 221600661643. The next prime is 221600661707. The reversal of 221600661667 is 766166006122.

It is a happy number.

It is not a de Polignac number, because 221600661667 - 2¹¹ = 221600659619 is a prime.

It is a super-3 number, since 3×221600661667³ (a number of 35 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (221600661067) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18711934 + ... + 18723772.

It is an arithmetic number, because the mean of its divisors is an integer number (4550112000).

Almost surely, 2^221600661667 is an apocalyptic number.

221600661667 is a deficient number, since it is larger than the sum of its proper divisors (69606506333).

221600661667 is an equidigital number, since it uses as much as digits as its factorization.

221600661667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11934 (or 11898 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 43.

Adding to 221600661667 its reverse (766166006122), we get a palindrome (987766667789).

The spelling of 221600661667 in words is "two hundred twenty-one billion, six hundred million, six hundred sixty-one thousand, six hundred sixty-seven".