221557557 has 8 divisors (see below), whose sum is σ = 318133984. Its totient is φ = 136343088.

The previous prime is 221557519. The next prime is 221557571. The reversal of 221557557 is 755755122.

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

It is a de Polignac number, because none of the positive numbers 2^k-221557557 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 5680963 = 221557557 / (2 + 2 + 1 + 5 + 5 + 7 + 5 + 5 + 7).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221557507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2840443 + ... + 2840520.

It is an arithmetic number, because the mean of its divisors is an integer number (39766748).

Almost surely, 2^221557557 is an apocalyptic number.

It is an amenable number.

221557557 is a deficient number, since it is larger than the sum of its proper divisors (96576427).

221557557 is a wasteful number, since it uses less digits than its factorization.

221557557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5680979.

The product of its digits is 122500, while the sum is 39.

The square root of 221557557 is about 14884.8096057692. The cubic root of 221557557 is about 605.1023727682.

The spelling of 221557557 in words is "two hundred twenty-one million, five hundred fifty-seven thousand, five hundred fifty-seven".