681722215969 has 2 divisors, whose sum is σ = 681722215970. Its totient is φ = 681722215968.

The previous prime is 681722215963. The next prime is 681722215997. The reversal of 681722215969 is 969512227186.

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., 622521000000 + 59201215969 = 789000^2 + 243313^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681722215969 is a prime.

It is a super-2 number, since 2×681722215969² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (681722215963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340861107984 + 340861107985.

It is an arithmetic number, because the mean of its divisors is an integer number (340861107985).

Almost surely, 2^681722215969 is an apocalyptic number.

It is an amenable number.

681722215969 is a deficient number, since it is larger than the sum of its proper divisors (1).

681722215969 is an equidigital number, since it uses as much as digits as its factorization.

681722215969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6531840, while the sum is 58.

The spelling of 681722215969 in words is "six hundred eighty-one billion, seven hundred twenty-two million, two hundred fifteen thousand, nine hundred sixty-nine".