81406287 has 6 divisors (see below), whose sum is σ = 117586872. Its totient is φ = 54270852.

The previous prime is 81406249. The next prime is 81406291. The reversal of 81406287 is 78260418.

It is not a de Polignac number, because 81406287 - 2⁷ = 81406159 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81406207) 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, 4522563 + ... + 4522580.

It is an arithmetic number, because the mean of its divisors is an integer number (19597812).

Almost surely, 2^81406287 is an apocalyptic number.

81406287 is a deficient number, since it is larger than the sum of its proper divisors (36180585).

81406287 is a wasteful number, since it uses less digits than its factorization.

81406287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9045149 (or 9045146 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 81406287 is about 9022.5432667292. The cubic root of 81406287 is about 433.3970812856.

The spelling of 81406287 in words is "eighty-one million, four hundred six thousand, two hundred eighty-seven".