81401117777 has 4 divisors (see below), whose sum is σ = 93029848896. Its totient is φ = 69772386660.

The previous prime is 81401117773. The next prime is 81401117827. The reversal of 81401117777 is 77771110418.

It is a happy number.

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: 77771110418 = 2 ⋅38885555209.

It is a cyclic number.

It is not a de Polignac number, because 81401117777 - 2² = 81401117773 is a prime.

It is a super-2 number, since 2×81401117777² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81401117773) 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, 5814365549 + ... + 5814365562.

It is an arithmetic number, because the mean of its divisors is an integer number (23257462224).

Almost surely, 2^81401117777 is an apocalyptic number.

It is an amenable number.

81401117777 is a deficient number, since it is larger than the sum of its proper divisors (11628731119).

81401117777 is a wasteful number, since it uses less digits than its factorization.

81401117777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11628731118.

The product of its (nonzero) digits is 76832, while the sum is 44.

The spelling of 81401117777 in words is "eighty-one billion, four hundred one million, one hundred seventeen thousand, seven hundred seventy-seven".