650001661 has 2 divisors, whose sum is σ = 650001662. Its totient is φ = 650001660.

The previous prime is 650001629. The next prime is 650001691. The reversal of 650001661 is 166100056.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 491996761 + 158004900 = 22181^2 + 12570^2 .

It is a cyclic number.

It is not a de Polignac number, because 650001661 - 2⁵ = 650001629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (650001601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 325000830 + 325000831.

It is an arithmetic number, because the mean of its divisors is an integer number (325000831).

Almost surely, 2^650001661 is an apocalyptic number.

It is an amenable number.

650001661 is a deficient number, since it is larger than the sum of its proper divisors (1).

650001661 is an equidigital number, since it uses as much as digits as its factorization.

650001661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 650001661 is about 25495.1301428332. The cubic root of 650001661 is about 866.2398431983.

The spelling of 650001661 in words is "six hundred fifty million, one thousand, six hundred sixty-one".