77980 has 24 divisors (see below), whose sum is σ = 187488. Its totient is φ = 26688.

The previous prime is 77977. The next prime is 77983. The reversal of 77980 is 8977.

It is an interprime number because it is at equal distance from previous prime (77977) and next prime (77983).

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 139 + ... + 418.

It is an arithmetic number, because the mean of its divisors is an integer number (7812).

2⁷⁷⁹⁸⁰ is an apocalyptic number.

77980 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

77980 is the 140-th decagonal number.

It is an amenable number.

77980 is an abundant number, since it is smaller than the sum of its proper divisors (109508).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93744).

77980 is a wasteful number, since it uses less digits than its factorization.

77980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 573 (or 571 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 31.

The square root of 77980 is about 279.2489928361. The cubic root of 77980 is about 42.7229346598.

The spelling of 77980 in words is "seventy-seven thousand, nine hundred eighty".