999640026767 has 2 divisors, whose sum is σ = 999640026768. Its totient is φ = 999640026766.

The previous prime is 999640026761. The next prime is 999640026811. The reversal of 999640026767 is 767620046999.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 999640026767 - 2¹⁰ = 999640025743 is a prime.

It is a super-2 number, since 2×999640026767² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999640026761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499820013383 + 499820013384.

It is an arithmetic number, because the mean of its divisors is an integer number (499820013384).

Almost surely, 2^999640026767 is an apocalyptic number.

999640026767 is a deficient number, since it is larger than the sum of its proper divisors (1).

999640026767 is an equidigital number, since it uses as much as digits as its factorization.

999640026767 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 61725888, while the sum is 65.

The spelling of 999640026767 in words is "nine hundred ninety-nine billion, six hundred forty million, twenty-six thousand, seven hundred sixty-seven".