81321450 has 96 divisors (see below), whose sum is σ = 236234880. Its totient is φ = 18124800.

The previous prime is 81321439. The next prime is 81321473. The reversal of 81321450 is 5412318.

It is a super-2 number, since 2×81321450² = 13226356460205000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81321450.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 42106 + ... + 43994.

It is an arithmetic number, because the mean of its divisors is an integer number (2460780).

Almost surely, 2^81321450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81321450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118117440).

81321450 is an abundant number, since it is smaller than the sum of its proper divisors (154913430).

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

81321450 is a wasteful number, since it uses less digits than its factorization.

81321450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1952 (or 1947 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 81321450 is about 9017.8406506214. The cubic root of 81321450 is about 433.2464750303.

Adding to 81321450 its reverse (5412318), we get a palindrome (86733768).

The spelling of 81321450 in words is "eighty-one million, three hundred twenty-one thousand, four hundred fifty".