81779590 has 8 divisors (see below), whose sum is σ = 147203280. Its totient is φ = 32711832.

The previous prime is 81779561. The next prime is 81779603. The reversal of 81779590 is 9597718.

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

It is a self number, because there is not a number n which added to its sum of digits gives 81779590.

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, 4088970 + ... + 4088989.

It is an arithmetic number, because the mean of its divisors is an integer number (18400410).

Almost surely, 2^81779590 is an apocalyptic number.

81779590 is a deficient number, since it is larger than the sum of its proper divisors (65423690).

81779590 is a wasteful number, since it uses less digits than its factorization.

81779590 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8177966.

The product of its (nonzero) digits is 158760, while the sum is 46.

The square root of 81779590 is about 9043.2068427080. The cubic root of 81779590 is about 434.0585443474.

It can be divided in two parts, 81779 and 590, that added together give a square (82369 = 287²).

The spelling of 81779590 in words is "eighty-one million, seven hundred seventy-nine thousand, five hundred ninety".