77118421 has 4 divisors (see below), whose sum is σ = 79606144. Its totient is φ = 74630700.

The previous prime is 77118403. The next prime is 77118427. The reversal of 77118421 is 12481177.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12481177 = 281 ⋅44417.

It is a cyclic number.

It is not a de Polignac number, because 77118421 - 2⁵ = 77118389 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 2487691 = 77118421 / (7 + 7 + 1 + 1 + 8 + 4 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77118427) 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, 1243815 + ... + 1243876.

It is an arithmetic number, because the mean of its divisors is an integer number (19901536).

Almost surely, 2^77118421 is an apocalyptic number.

It is an amenable number.

77118421 is a deficient number, since it is larger than the sum of its proper divisors (2487723).

77118421 is a wasteful number, since it uses less digits than its factorization.

77118421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2487722.

The product of its digits is 3136, while the sum is 31.

The square root of 77118421 is about 8781.7094577309. The cubic root of 77118421 is about 425.6500704425.

Adding to 77118421 its reverse (12481177), we get a palindrome (89599598).

The spelling of 77118421 in words is "seventy-seven million, one hundred eighteen thousand, four hundred twenty-one".