81367440 has 480 divisors, whose sum is σ = 348084864. Its totient is φ = 15482880.

The previous prime is 81367427. The next prime is 81367441. The reversal of 81367440 is 4476318.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81367441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2199102 + ... + 2199138.

Almost surely, 2^81367440 is an apocalyptic number.

81367440 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 81367440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (174042432).

81367440 is an abundant number, since it is smaller than the sum of its proper divisors (266717424).

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

81367440 is a wasteful number, since it uses less digits than its factorization.

81367440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 33.

The square root of 81367440 is about 9020.3902354610. The cubic root of 81367440 is about 433.3281314300.

It can be divided in two parts, 8136 and 7440, that added together give a triangular number (15576 = T₁₇₆).

The spelling of 81367440 in words is "eighty-one million, three hundred sixty-seven thousand, four hundred forty".