219889661 has 2 divisors, whose sum is σ = 219889662. Its totient is φ = 219889660.

The previous prime is 219889643. The next prime is 219889667. The reversal of 219889661 is 166988912.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 127825636 + 92064025 = 11306^2 + 9595^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-219889661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (219889667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109944830 + 109944831.

It is an arithmetic number, because the mean of its divisors is an integer number (109944831).

Almost surely, 2^219889661 is an apocalyptic number.

It is an amenable number.

219889661 is a deficient number, since it is larger than the sum of its proper divisors (1).

219889661 is an equidigital number, since it uses as much as digits as its factorization.

219889661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 50.

The square root of 219889661 is about 14828.6769807694. The cubic root of 219889661 is about 603.5801332178.

The spelling of 219889661 in words is "two hundred nineteen million, eight hundred eighty-nine thousand, six hundred sixty-one".