81487790 has 8 divisors (see below), whose sum is σ = 146678040. Its totient is φ = 32595112.

The previous prime is 81487771. The next prime is 81487799. The reversal of 81487790 is 9778418.

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 not an unprimeable number, because it can be changed into a prime (81487799) by changing a digit.

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, 4074380 + ... + 4074399.

It is an arithmetic number, because the mean of its divisors is an integer number (18334755).

Almost surely, 2^81487790 is an apocalyptic number.

81487790 is a deficient number, since it is larger than the sum of its proper divisors (65190250).

81487790 is a wasteful number, since it uses less digits than its factorization.

81487790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8148786.

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 81487790 is about 9027.0587679487. The cubic root of 81487790 is about 433.5416703658.

The spelling of 81487790 in words is "eighty-one million, four hundred eighty-seven thousand, seven hundred ninety".