8015651667721 has 2 divisors, whose sum is σ = 8015651667722. Its totient is φ = 8015651667720.

The previous prime is 8015651667703. The next prime is 8015651667767. The reversal of 8015651667721 is 1277661565108.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4099167129600 + 3916484538121 = 2024640^2 + 1979011^2 .

It is a cyclic number.

It is not a de Polignac number, because 8015651667721 - 2⁷ = 8015651667593 is a prime.

It is not a weakly prime, because it can be changed into another prime (8015651667521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4007825833860 + 4007825833861.

It is an arithmetic number, because the mean of its divisors is an integer number (4007825833861).

Almost surely, 2^{8015651667721} is an apocalyptic number.

It is an amenable number.

8015651667721 is a deficient number, since it is larger than the sum of its proper divisors (1).

8015651667721 is an equidigital number, since it uses as much as digits as its factorization.

8015651667721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4233600, while the sum is 55.

The spelling of 8015651667721 in words is "eight trillion, fifteen billion, six hundred fifty-one million, six hundred sixty-seven thousand, seven hundred twenty-one".