81045245 has 4 divisors (see below), whose sum is σ = 97254300. Its totient is φ = 64836192.

The previous prime is 81045199. The next prime is 81045247. The reversal of 81045245 is 54254018.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 23921881 + 57123364 = 4891^2 + 7558^2 .

It is a cyclic number.

It is not a de Polignac number, because 81045245 - 2¹⁴ = 81028861 is a prime.

It is a super-2 number, since 2×81045245² = 13136663474220050, which contains 22 as substring.

It is a Curzon number.

It is a nialpdrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81045247) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8104520 + ... + 8104529.

It is an arithmetic number, because the mean of its divisors is an integer number (24313575).

Almost surely, 2^81045245 is an apocalyptic number.

It is an amenable number.

81045245 is a deficient number, since it is larger than the sum of its proper divisors (16209055).

81045245 is a wasteful number, since it uses less digits than its factorization.

81045245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16209054.

The product of its (nonzero) digits is 6400, while the sum is 29.

The square root of 81045245 is about 9002.5132601957. The cubic root of 81045245 is about 432.7554173090.

The spelling of 81045245 in words is "eighty-one million, forty-five thousand, two hundred forty-five".