81862560 has 144 divisors (see below), whose sum is σ = 300913704. Its totient is φ = 20146176.

The previous prime is 81862541. The next prime is 81862619. The reversal of 81862560 is 6526818.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 54110736 + 27751824 = 7356^2 + 5268^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16534 + ... + 20906.

Almost surely, 2^81862560 is an apocalyptic number.

81862560 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 81862560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (150456852).

81862560 is an abundant number, since it is smaller than the sum of its proper divisors (219051144).

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

81862560 is a wasteful number, since it uses less digits than its factorization.

81862560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4407 (or 4396 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 81862560 is about 9047.7931010827. The cubic root of 81862560 is about 434.2052870123.

It can be divided in two parts, 81 and 862560, that added together give a triangular number (862641 = T₁₃₁₃).

The spelling of 81862560 in words is "eighty-one million, eight hundred sixty-two thousand, five hundred sixty".