81449550 has 360 divisors, whose sum is σ = 296539056. Its totient is φ = 16174080.

The previous prime is 81449549. The next prime is 81449581. The reversal of 81449550 is 5594418.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 179 ways as a sum of consecutive naturals, for example, 4791142 + ... + 4791158.

Almost surely, 2^81449550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81449550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148269528).

81449550 is an abundant number, since it is smaller than the sum of its proper divisors (215089506).

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

81449550 is a wasteful number, since it uses less digits than its factorization.

81449550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 81449550 is about 9024.9404430168. The cubic root of 81449550 is about 433.4738433231.

The spelling of 81449550 in words is "eighty-one million, four hundred forty-nine thousand, five hundred fifty".