221385761 has 2 divisors, whose sum is σ = 221385762. Its totient is φ = 221385760.

The previous prime is 221385757. The next prime is 221385767. The reversal of 221385761 is 167583122.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 199939600 + 21446161 = 14140^2 + 4631^2 .

It is a cyclic number.

It is not a de Polignac number, because 221385761 - 2² = 221385757 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221385767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110692880 + 110692881.

It is an arithmetic number, because the mean of its divisors is an integer number (110692881).

Almost surely, 2^221385761 is an apocalyptic number.

It is an amenable number.

221385761 is a deficient number, since it is larger than the sum of its proper divisors (1).

221385761 is an equidigital number, since it uses as much as digits as its factorization.

221385761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 35.

The square root of 221385761 is about 14879.0376368904. The cubic root of 221385761 is about 604.9459332874.

The spelling of 221385761 in words is "two hundred twenty-one million, three hundred eighty-five thousand, seven hundred sixty-one".