81573530407 has 16 divisors (see below), whose sum is σ = 84690790912. Its totient is φ = 78505251840.

The previous prime is 81573530399. The next prime is 81573530419. The reversal of 81573530407 is 70403537518.

It is a cyclic number.

It is not a de Polignac number, because 81573530407 - 2³ = 81573530399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81573530707) 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, 7362682 + ... + 7373752.

It is an arithmetic number, because the mean of its divisors is an integer number (5293174432).

Almost surely, 2^81573530407 is an apocalyptic number.

81573530407 is a deficient number, since it is larger than the sum of its proper divisors (3117260505).

81573530407 is a wasteful number, since it uses less digits than its factorization.

81573530407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13258.

The product of its (nonzero) digits is 352800, while the sum is 43.

The spelling of 81573530407 in words is "eighty-one billion, five hundred seventy-three million, five hundred thirty thousand, four hundred seven".