81401760 has 240 divisors, whose sum is σ = 313945632. Its totient is φ = 19699200.

The previous prime is 81401759. The next prime is 81401777. The reversal of 81401760 is 6710418.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 142275 + ... + 142845.

Almost surely, 2^81401760 is an apocalyptic number.

81401760 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 81401760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156972816).

81401760 is an abundant number, since it is smaller than the sum of its proper divisors (232543872).

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

81401760 is a wasteful number, since it uses less digits than its factorization.

81401760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609 (or 592 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 81401760 is about 9022.2923916264. The cubic root of 81401760 is about 433.3890474058.

The spelling of 81401760 in words is "eighty-one million, four hundred one thousand, seven hundred sixty".