19640997967 has 4 divisors (see below), whose sum is σ = 19677303496. Its totient is φ = 19604692440.

The previous prime is 19640997917. The next prime is 19640997977. The reversal of 19640997967 is 76979904691.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 76979904691 = 41 ⋅1877558651.

It is a cyclic number.

It is not a de Polignac number, because 19640997967 - 2⁷ = 19640997839 is a prime.

It is a super-2 number, since 2×19640997967² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19640997917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18151953 + ... + 18153034.

It is an arithmetic number, because the mean of its divisors is an integer number (4919325874).

Almost surely, 2^19640997967 is an apocalyptic number.

19640997967 is a deficient number, since it is larger than the sum of its proper divisors (36305529).

19640997967 is an equidigital number, since it uses as much as digits as its factorization.

19640997967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36305528.

The product of its (nonzero) digits is 46294416, while the sum is 67.

The spelling of 19640997967 in words is "nineteen billion, six hundred forty million, nine hundred ninety-seven thousand, nine hundred sixty-seven".