72116781 has 8 divisors (see below), whose sum is σ = 104897184. Its totient is φ = 43707120.

The previous prime is 72116741. The next prime is 72116783. The reversal of 72116781 is 18761127.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 72116781 - 2¹¹ = 72114733 is a prime.

It is a super-2 number, since 2×72116781² = 10401660203603922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 2185357 = 72116781 / (7 + 2 + 1 + 1 + 6 + 7 + 8 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72116783) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1092646 + ... + 1092711.

It is an arithmetic number, because the mean of its divisors is an integer number (13112148).

Almost surely, 2^72116781 is an apocalyptic number.

It is an amenable number.

72116781 is a deficient number, since it is larger than the sum of its proper divisors (32780403).

72116781 is a wasteful number, since it uses less digits than its factorization.

72116781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2185371.

The product of its digits is 4704, while the sum is 33.

The square root of 72116781 is about 8492.1599725865. The cubic root of 72116781 is about 416.2415637353.

The spelling of 72116781 in words is "seventy-two million, one hundred sixteen thousand, seven hundred eighty-one".