81440450 has 72 divisors (see below), whose sum is σ = 189839412. Its totient is φ = 25764480.

The previous prime is 81440449. The next prime is 81440459. The reversal of 81440450 is 5404418.

It can be written as a sum of positive squares in 6 ways, for example, as 13097161 + 68343289 = 3619^2 + 8267^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is not an unprimeable number, because it can be changed into a prime (81440459) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 30572 + ... + 33128.

Almost surely, 2^81440450 is an apocalyptic number.

81440450 is an abundant number, since it is smaller than the sum of its proper divisors (108398962).

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

81440450 is a wasteful number, since it uses less digits than its factorization.

81440450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2596 (or 2584 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 81440450 is about 9024.4362704825. The cubic root of 81440450 is about 433.4576993465.

Adding to 81440450 its reverse (5404418), we get a palindrome (86844868).

The spelling of 81440450 in words is "eighty-one million, four hundred forty thousand, four hundred fifty".