81387450 has 144 divisors (see below), whose sum is σ = 238109760. Its totient is φ = 20437920.

The previous prime is 81387443. The next prime is 81387473. The reversal of 81387450 is 5478318.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 487267 + ... + 487433.

It is an arithmetic number, because the mean of its divisors is an integer number (1653540).

Almost surely, 2^81387450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81387450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119054880).

81387450 is an abundant number, since it is smaller than the sum of its proper divisors (156722310).

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

81387450 is a wasteful number, since it uses less digits than its factorization.

81387450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 196 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 81387450 is about 9021.4993210663. The cubic root of 81387450 is about 433.3636500814.

It can be divided in two parts, 813 and 87450, that multiplied together give a triangular number (71096850 = T₁₁₉₂₄).

The spelling of 81387450 in words is "eighty-one million, three hundred eighty-seven thousand, four hundred fifty".