81485301825 has 72 divisors (see below), whose sum is σ = 149791414968. Its totient is φ = 42326768640.

The previous prime is 81485301823. The next prime is 81485301841. The reversal of 81485301825 is 52810358418.

81485301825 is a `hidden beast` number, since 81 + 4 + 8 + 530 + 18 + 25 = 666.

It can be written as a sum of positive squares in 12 ways, for example, as 33503275521 + 47982026304 = 183039^2 + 219048^2 .

It is not a de Polignac number, because 81485301825 - 2¹ = 81485301823 is a prime.

It is a super-2 number, since 2×81485301825² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81485301823) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1608787 + ... + 1658663.

It is an arithmetic number, because the mean of its divisors is an integer number (2080436319).

Almost surely, 2^81485301825 is an apocalyptic number.

It is an amenable number.

81485301825 is a deficient number, since it is larger than the sum of its proper divisors (68306113143).

81485301825 is a wasteful number, since it uses less digits than its factorization.

81485301825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50083 (or 50075 counting only the distinct ones).

The product of its (nonzero) digits is 307200, while the sum is 45.

The spelling of 81485301825 in words is "eighty-one billion, four hundred eighty-five million, three hundred one thousand, eight hundred twenty-five".