81569671039 has 4 divisors (see below), whose sum is σ = 85862811640. Its totient is φ = 77276530440.

The previous prime is 81569671037. The next prime is 81569671049. The reversal of 81569671039 is 93017696518.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 81569671039 - 2¹ = 81569671037 is a prime.

It is a super-2 number, since 2×81569671039² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81569671037) 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, 2146570272 + ... + 2146570309.

It is an arithmetic number, because the mean of its divisors is an integer number (21465702910).

Almost surely, 2^81569671039 is an apocalyptic number.

81569671039 is a deficient number, since it is larger than the sum of its proper divisors (4293140601).

81569671039 is a wasteful number, since it uses less digits than its factorization.

81569671039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4293140600.

The product of its (nonzero) digits is 2449440, while the sum is 55.

The spelling of 81569671039 in words is "eighty-one billion, five hundred sixty-nine million, six hundred seventy-one thousand, thirty-nine".