221561057 has 2 divisors, whose sum is σ = 221561058. Its totient is φ = 221561056.

The previous prime is 221560991. The next prime is 221561077. The reversal of 221561057 is 750165122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 145540096 + 76020961 = 12064^2 + 8719^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221561057 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221561077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110780528 + 110780529.

It is an arithmetic number, because the mean of its divisors is an integer number (110780529).

Almost surely, 2^221561057 is an apocalyptic number.

It is an amenable number.

221561057 is a deficient number, since it is larger than the sum of its proper divisors (1).

221561057 is an equidigital number, since it uses as much as digits as its factorization.

221561057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4200, while the sum is 29.

The square root of 221561057 is about 14884.9271748302. The cubic root of 221561057 is about 605.1055590691.

The spelling of 221561057 in words is "two hundred twenty-one million, five hundred sixty-one thousand, fifty-seven".