8720023661 has 2 divisors, whose sum is σ = 8720023662. Its totient is φ = 8720023660.

The previous prime is 8720023619. The next prime is 8720023679. The reversal of 8720023661 is 1663200278.

It is a happy number.

8720023661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8587543561 + 132480100 = 92669^2 + 11510^2 .

It is a cyclic number.

It is not a de Polignac number, because 8720023661 - 2¹⁸ = 8719761517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8720023691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4360011830 + 4360011831.

It is an arithmetic number, because the mean of its divisors is an integer number (4360011831).

Almost surely, 2^8720023661 is an apocalyptic number.

It is an amenable number.

8720023661 is a deficient number, since it is larger than the sum of its proper divisors (1).

8720023661 is an equidigital number, since it uses as much as digits as its factorization.

8720023661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 8720023661 is about 93381.0669300796. The cubic root of 8720023661 is about 2058.2867948034.

The spelling of 8720023661 in words is "eight billion, seven hundred twenty million, twenty-three thousand, six hundred sixty-one".