81775488 has 128 divisors (see below), whose sum is σ = 232657920. Its totient is φ = 25389056.

The previous prime is 81775483. The next prime is 81775493. The reversal of 81775488 is 88457718.

It is an interprime number because it is at equal distance from previous prime (81775483) and next prime (81775493).

It is a tau number, because it is divible by the number of its divisors (128).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81775481) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 415006 + ... + 415202.

It is an arithmetic number, because the mean of its divisors is an integer number (1817640).

Almost surely, 2^81775488 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81775488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116328960).

81775488 is an abundant number, since it is smaller than the sum of its proper divisors (150882432).

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

81775488 is a wasteful number, since it uses less digits than its factorization.

81775488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284 (or 272 counting only the distinct ones).

The product of its digits is 501760, while the sum is 48.

The square root of 81775488 is about 9042.9800397878. The cubic root of 81775488 is about 434.0512868808.

The spelling of 81775488 in words is "eighty-one million, seven hundred seventy-five thousand, four hundred eighty-eight".