81243075 has 12 divisors (see below), whose sum is σ = 134322008. Its totient is φ = 43329600.

The previous prime is 81243023. The next prime is 81243077. The reversal of 81243075 is 57034218.

It is not a de Polignac number, because 81243075 - 2⁹ = 81242563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81243077) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 541546 + ... + 541695.

Almost surely, 2^81243075 is an apocalyptic number.

81243075 is a deficient number, since it is larger than the sum of its proper divisors (53078933).

81243075 is a wasteful number, since it uses less digits than its factorization.

81243075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1083254 (or 1083249 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 81243075 is about 9013.4940505888. The cubic root of 81243075 is about 433.1072472833.

The spelling of 81243075 in words is "eighty-one million, two hundred forty-three thousand, seventy-five".