4020507661 has 2 divisors, whose sum is σ = 4020507662. Its totient is φ = 4020507660.

The previous prime is 4020507643. The next prime is 4020507691. The reversal of 4020507661 is 1667050204.

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., 3869586436 + 150921225 = 62206^2 + 12285^2 .

It is a cyclic number.

It is not a de Polignac number, because 4020507661 - 2⁵ = 4020507629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4020507641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2010253830 + 2010253831.

It is an arithmetic number, because the mean of its divisors is an integer number (2010253831).

Almost surely, 2^4020507661 is an apocalyptic number.

It is an amenable number.

4020507661 is a deficient number, since it is larger than the sum of its proper divisors (1).

4020507661 is an equidigital number, since it uses as much as digits as its factorization.

4020507661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 4020507661 is about 63407.4732267420. The cubic root of 4020507661 is about 1590.1092525432.

Adding to 4020507661 its reverse (1667050204), we get a palindrome (5687557865).

The spelling of 4020507661 in words is "four billion, twenty million, five hundred seven thousand, six hundred sixty-one".