77121791 has 8 divisors (see below), whose sum is σ = 78675840. Its totient is φ = 75576088.

The previous prime is 77121773. The next prime is 77121797. The reversal of 77121791 is 19712177.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77121791 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77121797) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18590 + ... + 22356.

It is an arithmetic number, because the mean of its divisors is an integer number (9834480).

Almost surely, 2^77121791 is an apocalyptic number.

77121791 is a deficient number, since it is larger than the sum of its proper divisors (1554049).

77121791 is a wasteful number, since it uses less digits than its factorization.

77121791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4173.

The product of its digits is 6174, while the sum is 35.

The square root of 77121791 is about 8781.9013317163. The cubic root of 77121791 is about 425.6562705169.

It can be divided in two parts, 771 and 21791, that multiplied together give a palindrome (16800861).

The spelling of 77121791 in words is "seventy-seven million, one hundred twenty-one thousand, seven hundred ninety-one".