77978141 has 4 divisors (see below), whose sum is σ = 78244572. Its totient is φ = 77711712.

The previous prime is 77978137. The next prime is 77978171. The reversal of 77978141 is 14187977.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 14187977 = 313 ⋅45329.

It can be written as a sum of positive squares in 2 ways, for example, as 71995225 + 5982916 = 8485^2 + 2446^2 .

It is a cyclic number.

It is not a de Polignac number, because 77978141 - 2² = 77978137 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 77978092 and 77978101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77978111) 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, 132776 + ... + 133361.

It is an arithmetic number, because the mean of its divisors is an integer number (19561143).

Almost surely, 2^77978141 is an apocalyptic number.

It is an amenable number.

77978141 is a deficient number, since it is larger than the sum of its proper divisors (266431).

77978141 is a wasteful number, since it uses less digits than its factorization.

77978141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266430.

The product of its digits is 98784, while the sum is 44.

The square root of 77978141 is about 8830.5232574293. The cubic root of 77978141 is about 427.2259516005.

The spelling of 77978141 in words is "seventy-seven million, nine hundred seventy-eight thousand, one hundred forty-one".