77781438871 has 4 divisors (see below), whose sum is σ = 77782664232. Its totient is φ = 77780213512.

The previous prime is 77781438829. The next prime is 77781438913. The reversal of 77781438871 is 17883418777.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (77781438829) and next prime (77781438913).

It is a cyclic number.

It is not a de Polignac number, because 77781438871 - 2⁷ = 77781438743 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 (77781438811) 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, 511945 + ... + 646258.

It is an arithmetic number, because the mean of its divisors is an integer number (19445666058).

Almost surely, 2^77781438871 is an apocalyptic number.

77781438871 is a deficient number, since it is larger than the sum of its proper divisors (1225361).

77781438871 is a wasteful number, since it uses less digits than its factorization.

77781438871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1225360.

The product of its digits is 14751744, while the sum is 61.

The spelling of 77781438871 in words is "seventy-seven billion, seven hundred eighty-one million, four hundred thirty-eight thousand, eight hundred seventy-one".