81550077 has 16 divisors (see below), whose sum is σ = 125665920. Its totient is φ = 46075392.

The previous prime is 81550069. The next prime is 81550087. The reversal of 81550077 is 77005518.

It is not a de Polignac number, because 81550077 - 2³ = 81550069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81550087) 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 15 ways as a sum of consecutive naturals, for example, 19948 + ... + 23685.

It is an arithmetic number, because the mean of its divisors is an integer number (7854120).

Almost surely, 2^81550077 is an apocalyptic number.

It is an amenable number.

81550077 is a deficient number, since it is larger than the sum of its proper divisors (44115843).

81550077 is a wasteful number, since it uses less digits than its factorization.

81550077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43732.

The product of its (nonzero) digits is 9800, while the sum is 33.

The square root of 81550077 is about 9030.5081252386. The cubic root of 81550077 is about 433.6521046308.

The spelling of 81550077 in words is "eighty-one million, five hundred fifty thousand, seventy-seven".