81409224 has 128 divisors (see below), whose sum is σ = 238694400. Its totient is φ = 22913280.

The previous prime is 81409189. The next prime is 81409241. The reversal of 81409224 is 42290418.

It is a junction number, because it is equal to n+sod(n) for n = 81409191 and 81409200.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 183547 + ... + 183989.

It is an arithmetic number, because the mean of its divisors is an integer number (1864800).

Almost surely, 2^81409224 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81409224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119347200).

81409224 is an abundant number, since it is smaller than the sum of its proper divisors (157285176).

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

81409224 is a wasteful number, since it uses less digits than its factorization.

81409224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515 (or 511 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 81409224 is about 9022.7060242479. The cubic root of 81409224 is about 433.4022932987.

The spelling of 81409224 in words is "eighty-one million, four hundred nine thousand, two hundred twenty-four".