8502721861 has 2 divisors, whose sum is σ = 8502721862. Its totient is φ = 8502721860.

The previous prime is 8502721847. The next prime is 8502721963. The reversal of 8502721861 is 1681272058.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7013225025 + 1489496836 = 83745^2 + 38594^2 .

It is a cyclic number.

It is not a de Polignac number, because 8502721861 - 2²¹ = 8500624709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8502721561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4251360930 + 4251360931.

It is an arithmetic number, because the mean of its divisors is an integer number (4251360931).

Almost surely, 2^8502721861 is an apocalyptic number.

It is an amenable number.

8502721861 is a deficient number, since it is larger than the sum of its proper divisors (1).

8502721861 is an equidigital number, since it uses as much as digits as its factorization.

8502721861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 53760, while the sum is 40.

The square root of 8502721861 is about 92210.2047552222. The cubic root of 8502721861 is about 2041.0453649234.

The spelling of 8502721861 in words is "eight billion, five hundred two million, seven hundred twenty-one thousand, eight hundred sixty-one".