81767402011 has 4 divisors (see below), whose sum is σ = 81785170552. Its totient is φ = 81749633472.

The previous prime is 81767401973. The next prime is 81767402021. The reversal of 81767402011 is 11020476718.

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

It is a cyclic number.

It is not a de Polignac number, because 81767402011 - 2³⁵ = 47407663643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81767402021) 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, 8877366 + ... + 8886571.

It is an arithmetic number, because the mean of its divisors is an integer number (20446292638).

Almost surely, 2^81767402011 is an apocalyptic number.

81767402011 is a deficient number, since it is larger than the sum of its proper divisors (17768541).

81767402011 is a wasteful number, since it uses less digits than its factorization.

81767402011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17768540.

The product of its (nonzero) digits is 18816, while the sum is 37.

Adding to 81767402011 its reverse (11020476718), we get a palindrome (92787878729).

The spelling of 81767402011 in words is "eighty-one billion, seven hundred sixty-seven million, four hundred two thousand, eleven".