1977967945 has 4 divisors (see below), whose sum is σ = 2373561540. Its totient is φ = 1582374352.

The previous prime is 1977967931. The next prime is 1977967949. The reversal of 1977967945 is 5497697791.

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

It can be written as a sum of positive squares in 2 ways, for example, as 208167184 + 1769800761 = 14428^2 + 42069^2 .

It is a cyclic number.

It is not a de Polignac number, because 1977967945 - 2²⁷ = 1843750217 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1977967949) 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, 197796790 + ... + 197796799.

It is an arithmetic number, because the mean of its divisors is an integer number (593390385).

Almost surely, 2^1977967945 is an apocalyptic number.

It is an amenable number.

1977967945 is a deficient number, since it is larger than the sum of its proper divisors (395593595).

1977967945 is an equidigital number, since it uses as much as digits as its factorization.

1977967945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395593594.

The product of its digits is 30005640, while the sum is 64.

The square root of 1977967945 is about 44474.3515410849. The cubic root of 1977967945 is about 1255.2775151756.

The spelling of 1977967945 in words is "one billion, nine hundred seventy-seven million, nine hundred sixty-seven thousand, nine hundred forty-five".