221605557151 has 4 divisors (see below), whose sum is σ = 241751516904. Its totient is φ = 201459597400.

The previous prime is 221605557137. The next prime is 221605557157. The reversal of 221605557151 is 151755506122.

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

It is a cyclic number.

It is not a de Polignac number, because 221605557151 - 2¹⁹ = 221605032863 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 (221605557157) 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, 10072979860 + ... + 10072979881.

It is an arithmetic number, because the mean of its divisors is an integer number (60437879226).

Almost surely, 2^221605557151 is an apocalyptic number.

221605557151 is a deficient number, since it is larger than the sum of its proper divisors (20145959753).

221605557151 is a wasteful number, since it uses less digits than its factorization.

221605557151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20145959752.

The product of its (nonzero) digits is 105000, while the sum is 40.

The spelling of 221605557151 in words is "two hundred twenty-one billion, six hundred five million, five hundred fifty-seven thousand, one hundred fifty-one".