81403911 has 6 divisors (see below), whose sum is σ = 117583440. Its totient is φ = 54269268.

The previous prime is 81403867. The next prime is 81403921. The reversal of 81403911 is 11930418.

It is not a de Polignac number, because 81403911 - 2¹⁷ = 81272839 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81403921) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4522431 + ... + 4522448.

It is an arithmetic number, because the mean of its divisors is an integer number (19597240).

Almost surely, 2^81403911 is an apocalyptic number.

81403911 is a deficient number, since it is larger than the sum of its proper divisors (36179529).

81403911 is a wasteful number, since it uses less digits than its factorization.

81403911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9044885 (or 9044882 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 81403911 is about 9022.4115955769. The cubic root of 81403911 is about 433.3928647338.

The spelling of 81403911 in words is "eighty-one million, four hundred three thousand, nine hundred eleven".