81591406 has 8 divisors (see below), whose sum is σ = 131801544. Its totient is φ = 37657560.

The previous prime is 81591383. The next prime is 81591431. The reversal of 81591406 is 60419518.

81591406 is nontrivially palindromic in base 3.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1569040 + ... + 1569091.

It is an arithmetic number, because the mean of its divisors is an integer number (16475193).

Almost surely, 2^81591406 is an apocalyptic number.

81591406 is a deficient number, since it is larger than the sum of its proper divisors (50210138).

81591406 is a wasteful number, since it uses less digits than its factorization.

81591406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3138146.

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 81591406 is about 9032.7961340883. The cubic root of 81591406 is about 433.7253495280.

The spelling of 81591406 in words is "eighty-one million, five hundred ninety-one thousand, four hundred six".