81448945 has 4 divisors (see below), whose sum is σ = 97738740. Its totient is φ = 65159152.

The previous prime is 81448943. The next prime is 81448963. The reversal of 81448945 is 54984418.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54984418 = 2 ⋅27492209.

It can be written as a sum of positive squares in 2 ways, for example, as 41113744 + 40335201 = 6412^2 + 6351^2 .

It is a cyclic number.

It is not a de Polignac number, because 81448945 - 2¹ = 81448943 is a prime.

It is a super-2 number, since 2×81448945² = 13267861283226050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81448943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8144890 + ... + 8144899.

It is an arithmetic number, because the mean of its divisors is an integer number (24434685).

Almost surely, 2^81448945 is an apocalyptic number.

It is an amenable number.

81448945 is a deficient number, since it is larger than the sum of its proper divisors (16289795).

81448945 is a wasteful number, since it uses less digits than its factorization.

81448945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16289794.

The product of its digits is 184320, while the sum is 43.

The square root of 81448945 is about 9024.9069247278. The cubic root of 81448945 is about 433.4727700520.

The spelling of 81448945 in words is "eighty-one million, four hundred forty-eight thousand, nine hundred forty-five".