72158361281 has 4 divisors (see below), whose sum is σ = 72196806612. Its totient is φ = 72119915952.

The previous prime is 72158361257. The next prime is 72158361287. The reversal of 72158361281 is 18216385127.

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

It can be written as a sum of positive squares in 2 ways, for example, as 45706591681 + 26451769600 = 213791^2 + 162640^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72158361281 is a prime.

It is a super-2 number, since 2×72158361281² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72158361287) 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, 19219850 + ... + 19223603.

It is an arithmetic number, because the mean of its divisors is an integer number (18049201653).

Almost surely, 2^72158361281 is an apocalyptic number.

It is an amenable number.

72158361281 is a deficient number, since it is larger than the sum of its proper divisors (38445331).

72158361281 is a wasteful number, since it uses less digits than its factorization.

72158361281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38445330.

The product of its digits is 161280, while the sum is 44.

The spelling of 72158361281 in words is "seventy-two billion, one hundred fifty-eight million, three hundred sixty-one thousand, two hundred eighty-one".