81177120 has 384 divisors, whose sum is σ = 319334400. Its totient is φ = 19160064.

The previous prime is 81177113. The next prime is 81177121. The reversal of 81177120 is 2177118.

It is a super-2 number, since 2×81177120² = 13179449622988800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (81177121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1887819 + ... + 1887861.

It is an arithmetic number, because the mean of its divisors is an integer number (831600).

Almost surely, 2^81177120 is an apocalyptic number.

81177120 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81177120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159667200).

81177120 is an abundant number, since it is smaller than the sum of its proper divisors (238157280).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81177120 is a wasteful number, since it uses less digits than its factorization.

81177120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 95 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 27.

The square root of 81177120 is about 9009.8346266732. The cubic root of 81177120 is about 432.9900134060.

The spelling of 81177120 in words is "eighty-one million, one hundred seventy-seven thousand, one hundred twenty".