81077558 has 4 divisors (see below), whose sum is σ = 121616340. Its totient is φ = 40538778.

The previous prime is 81077551. The next prime is 81077561. The reversal of 81077558 is 85577018.

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

It is a super-2 number, since 2×81077558² = 13147140822486728, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81077551) by changing a digit.

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, 20269388 + ... + 20269391.

It is an arithmetic number, because the mean of its divisors is an integer number (30404085).

Almost surely, 2^81077558 is an apocalyptic number.

81077558 is a deficient number, since it is larger than the sum of its proper divisors (40538782).

81077558 is a wasteful number, since it uses less digits than its factorization.

81077558 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40538781.

The product of its (nonzero) digits is 78400, while the sum is 41.

The square root of 81077558 is about 9004.3077468509. The cubic root of 81077558 is about 432.8129233263.

The spelling of 81077558 in words is "eighty-one million, seventy-seven thousand, five hundred fifty-eight".