81177429877 has 4 divisors (see below), whose sum is σ = 82389033376. Its totient is φ = 79965826380.

The previous prime is 81177429863. The next prime is 81177429887. The reversal of 81177429877 is 77892477118.

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.

It is a cyclic number.

It is not a de Polignac number, because 81177429877 - 2²⁷ = 81043212149 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 (81177429857) 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, 605801649 + ... + 605801782.

It is an arithmetic number, because the mean of its divisors is an integer number (20597258344).

Almost surely, 2^81177429877 is an apocalyptic number.

It is an amenable number.

81177429877 is a deficient number, since it is larger than the sum of its proper divisors (1211603499).

81177429877 is a wasteful number, since it uses less digits than its factorization.

81177429877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1211603498.

The product of its digits is 11063808, while the sum is 61.

The spelling of 81177429877 in words is "eighty-one billion, one hundred seventy-seven million, four hundred twenty-nine thousand, eight hundred seventy-seven".