1979780777 has 4 divisors (see below), whose sum is σ = 2132071620. Its totient is φ = 1827489936.

The previous prime is 1979780773. The next prime is 1979780797. The reversal of 1979780777 is 7770879791.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7770879791 = 757 ⋅10265363.

It can be written as a sum of positive squares in 2 ways, for example, as 987467776 + 992313001 = 31424^2 + 31501^2 .

It is a cyclic number.

It is not a de Polignac number, because 1979780777 - 2² = 1979780773 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1979780773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 76145402 + ... + 76145427.

It is an arithmetic number, because the mean of its divisors is an integer number (533017905).

Almost surely, 2^1979780777 is an apocalyptic number.

It is an amenable number.

1979780777 is a deficient number, since it is larger than the sum of its proper divisors (152290843).

1979780777 is a wasteful number, since it uses less digits than its factorization.

1979780777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152290842.

The product of its (nonzero) digits is 10890936, while the sum is 62.

The square root of 1979780777 is about 44494.7275191117. The cubic root of 1979780777 is about 1255.6608905147.

The spelling of 1979780777 in words is "one billion, nine hundred seventy-nine million, seven hundred eighty thousand, seven hundred seventy-seven".