81449956 has 36 divisors (see below), whose sum is σ = 166981500. Its totient is φ = 34660416.

The previous prime is 81449939. The next prime is 81449971. The reversal of 81449956 is 65994418.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 28451556 + 52998400 = 5334^2 + 7280^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27810 + ... + 30598.

It is an arithmetic number, because the mean of its divisors is an integer number (4638375).

Almost surely, 2^81449956 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 81449956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83490750).

81449956 is an abundant number, since it is smaller than the sum of its proper divisors (85531544).

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

81449956 is a wasteful number, since it uses less digits than its factorization.

81449956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2956 (or 2947 counting only the distinct ones).

The product of its digits is 311040, while the sum is 46.

The square root of 81449956 is about 9024.9629362120. The cubic root of 81449956 is about 433.4745635648.

The spelling of 81449956 in words is "eighty-one million, four hundred forty-nine thousand, nine hundred fifty-six".