72871809817 has 4 divisors (see below), whose sum is σ = 73354404736. Its totient is φ = 72389214900.

The previous prime is 72871809779. The next prime is 72871809821. The reversal of 72871809817 is 71890817827.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 72871809817 - 2¹¹ = 72871807769 is a prime.

It is a super-3 number, since 3×72871809817³ (a number of 34 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72871809617) 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, 241297233 + ... + 241297534.

It is an arithmetic number, because the mean of its divisors is an integer number (18338601184).

Almost surely, 2^72871809817 is an apocalyptic number.

It is an amenable number.

72871809817 is a deficient number, since it is larger than the sum of its proper divisors (482594919).

72871809817 is a wasteful number, since it uses less digits than its factorization.

72871809817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 482594918.

The product of its (nonzero) digits is 3161088, while the sum is 58.

It can be divided in two parts, 7287 and 1809817, that added together give a square (1817104 = 1348²).

The spelling of 72871809817 in words is "seventy-two billion, eight hundred seventy-one million, eight hundred nine thousand, eight hundred seventeen".