221766137 has 2 divisors, whose sum is σ = 221766138. Its totient is φ = 221766136.

The previous prime is 221766109. The next prime is 221766169. The reversal of 221766137 is 731667122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 221087161 + 678976 = 14869^2 + 824^2 .

It is a cyclic number.

It is not a de Polignac number, because 221766137 - 2¹⁰ = 221765113 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221766097 and 221766106.

It is not a weakly prime, because it can be changed into another prime (221766187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110883068 + 110883069.

It is an arithmetic number, because the mean of its divisors is an integer number (110883069).

Almost surely, 2^221766137 is an apocalyptic number.

It is an amenable number.

221766137 is a deficient number, since it is larger than the sum of its proper divisors (1).

221766137 is an equidigital number, since it uses as much as digits as its factorization.

221766137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 35.

The square root of 221766137 is about 14891.8144294105. The cubic root of 221766137 is about 605.2921995395.

The spelling of 221766137 in words is "two hundred twenty-one million, seven hundred sixty-six thousand, one hundred thirty-seven".