81248945 has 16 divisors (see below), whose sum is σ = 98960400. Its totient is φ = 64032000.

The previous prime is 81248941. The next prime is 81248953. The reversal of 81248945 is 54984218.

It can be written as a sum of positive squares in 8 ways, for example, as 5053504 + 76195441 = 2248^2 + 8729^2 .

It is not a de Polignac number, because 81248945 - 2² = 81248941 is a prime.

It is a super-2 number, since 2×81248945² = 13202782127226050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81248941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 176015 + ... + 176475.

It is an arithmetic number, because the mean of its divisors is an integer number (6185025).

Almost surely, 2^81248945 is an apocalyptic number.

It is an amenable number.

81248945 is a deficient number, since it is larger than the sum of its proper divisors (17711455).

81248945 is a wasteful number, since it uses less digits than its factorization.

81248945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 916.

The product of its digits is 92160, while the sum is 41.

The square root of 81248945 is about 9013.8196675993. The cubic root of 81248945 is about 433.1176780321.

The spelling of 81248945 in words is "eighty-one million, two hundred forty-eight thousand, nine hundred forty-five".