81877594 has 4 divisors (see below), whose sum is σ = 122816394. Its totient is φ = 40938796.

The previous prime is 81877589. The next prime is 81877637. The reversal of 81877594 is 49577818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 78943225 + 2934369 = 8885^2 + 1713^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20469397 + ... + 20469400.

Almost surely, 2^81877594 is an apocalyptic number.

81877594 is a deficient number, since it is larger than the sum of its proper divisors (40938800).

81877594 is a wasteful number, since it uses less digits than its factorization.

81877594 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40938799.

The product of its digits is 564480, while the sum is 49.

The square root of 81877594 is about 9048.6238732749. The cubic root of 81877594 is about 434.2318658811.

The spelling of 81877594 in words is "eighty-one million, eight hundred seventy-seven thousand, five hundred ninety-four".