81187478 has 8 divisors (see below), whose sum is σ = 128944872. Its totient is φ = 38205856.

The previous prime is 81187459. The next prime is 81187489. The reversal of 81187478 is 87478118.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1193900 + ... + 1193967.

It is an arithmetic number, because the mean of its divisors is an integer number (16118109).

Almost surely, 2^81187478 is an apocalyptic number.

81187478 is a deficient number, since it is larger than the sum of its proper divisors (47757394).

81187478 is a wasteful number, since it uses less digits than its factorization.

81187478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2387886.

The product of its digits is 100352, while the sum is 44.

The square root of 81187478 is about 9010.4094246599. The cubic root of 81187478 is about 433.0084287749.

The spelling of 81187478 in words is "eighty-one million, one hundred eighty-seven thousand, four hundred seventy-eight".