81521240045 has 32 divisors (see below), whose sum is σ = 113258476800. Its totient is φ = 55172643840.

The previous prime is 81521240027. The next prime is 81521240057. The reversal of 81521240045 is 54004212518.

It is not a de Polignac number, because 81521240045 - 2⁶ = 81521239981 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81521239993 and 81521240020.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3068981 + ... + 3095429.

It is an arithmetic number, because the mean of its divisors is an integer number (3539327400).

Almost surely, 2^81521240045 is an apocalyptic number.

It is an amenable number.

81521240045 is a deficient number, since it is larger than the sum of its proper divisors (31737236755).

81521240045 is a wasteful number, since it uses less digits than its factorization.

81521240045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27605.

The product of its (nonzero) digits is 12800, while the sum is 32.

The spelling of 81521240045 in words is "eighty-one billion, five hundred twenty-one million, two hundred forty thousand, forty-five".