1966540989979 has 4 divisors (see below), whose sum is σ = 2052042772176. Its totient is φ = 1881039207784.

The previous prime is 1966540989967. The next prime is 1966540989991. The reversal of 1966540989979 is 9799890456691.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1966540989967) and next prime (1966540989991).

It is a cyclic number.

It is not a de Polignac number, because 1966540989979 - 2⁷ = 1966540989851 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1966540989779) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42750891064 + ... + 42750891109.

It is an arithmetic number, because the mean of its divisors is an integer number (513010693044).

Almost surely, 2^{1966540989979} is an apocalyptic number.

1966540989979 is a deficient number, since it is larger than the sum of its proper divisors (85501782197).

1966540989979 is an equidigital number, since it uses as much as digits as its factorization.

1966540989979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85501782196.

The product of its (nonzero) digits is 2380855680, while the sum is 82.

The spelling of 1966540989979 in words is "one trillion, nine hundred sixty-six billion, five hundred forty million, nine hundred eighty-nine thousand, nine hundred seventy-nine".