81777648 has 40 divisors (see below), whose sum is σ = 213142608. Its totient is φ = 27016192.

The previous prime is 81777643. The next prime is 81777649. The reversal of 81777648 is 84677718.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a junction number, because it is equal to n+sod(n) for n = 81777597 and 81777606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81777643) 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 7 ways as a sum of consecutive naturals, for example, 2115 + ... + 12962.

Almost surely, 2^81777648 is an apocalyptic number.

It is an amenable number.

81777648 is an abundant number, since it is smaller than the sum of its proper divisors (131364960).

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

81777648 is a wasteful number, since it uses less digits than its factorization.

81777648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15201 (or 15195 counting only the distinct ones).

The product of its digits is 526848, while the sum is 48.

The square root of 81777648 is about 9043.0994686556. The cubic root of 81777648 is about 434.0551084927.

The spelling of 81777648 in words is "eighty-one million, seven hundred seventy-seven thousand, six hundred forty-eight".