81861360 has 120 divisors (see below), whose sum is σ = 295244496. Its totient is φ = 18708480.

The previous prime is 81861349. The next prime is 81861389. The reversal of 81861360 is 6316818.

81861360 = T₅ + T₆ + ... + T₇₈₈.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×81861360² = 13402564522099200, which contains 22 as substring.

It is a congruent number.

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, 8280 + ... + 15240.

Almost surely, 2^81861360 is an apocalyptic number.

81861360 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 81861360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147622248).

81861360 is an abundant number, since it is smaller than the sum of its proper divisors (213383136).

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

81861360 is a wasteful number, since it uses less digits than its factorization.

81861360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6991 (or 6978 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 81861360 is about 9047.7267863259. The cubic root of 81861360 is about 434.2031653713.

The spelling of 81861360 in words is "eighty-one million, eight hundred sixty-one thousand, three hundred sixty".