8520502661981 has 2 divisors, whose sum is σ = 8520502661982. Its totient is φ = 8520502661980.

The previous prime is 8520502661953. The next prime is 8520502662043. The reversal of 8520502661981 is 1891662050258.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4889538112900 + 3630964549081 = 2211230^2 + 1905509^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8520502661981 is a prime.

It is a super-2 number, since 2×8520502661981² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8520502661941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4260251330990 + 4260251330991.

It is an arithmetic number, because the mean of its divisors is an integer number (4260251330991).

Almost surely, 2^{8520502661981} is an apocalyptic number.

It is an amenable number.

8520502661981 is a deficient number, since it is larger than the sum of its proper divisors (1).

8520502661981 is an equidigital number, since it uses as much as digits as its factorization.

8520502661981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2073600, while the sum is 53.

The spelling of 8520502661981 in words is "eight trillion, five hundred twenty billion, five hundred two million, six hundred sixty-one thousand, nine hundred eighty-one".