81677280 has 96 divisors (see below), whose sum is σ = 258660864. Its totient is φ = 21664256.

The previous prime is 81677263. The next prime is 81677287. The reversal of 81677280 is 8277618.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81677287) 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, 125917 + ... + 126563.

It is an arithmetic number, because the mean of its divisors is an integer number (2694384).

Almost surely, 2^81677280 is an apocalyptic number.

81677280 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 81677280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129330432).

81677280 is an abundant number, since it is smaller than the sum of its proper divisors (176983584).

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

81677280 is a wasteful number, since it uses less digits than its factorization.

81677280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 928 (or 920 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 39.

The square root of 81677280 is about 9037.5483401197. The cubic root of 81677280 is about 433.8774597940.

The spelling of 81677280 in words is "eighty-one million, six hundred seventy-seven thousand, two hundred eighty".