72283681 has 4 divisors (see below), whose sum is σ = 74237332. Its totient is φ = 70330032.

The previous prime is 72283667. The next prime is 72283691. The reversal of 72283681 is 18638227.

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 40755456 + 31528225 = 6384^2 + 5615^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72283681 is a prime.

It is a super-2 number, since 2×72283681² = 10449861077819522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 1953613 = 72283681 / (7 + 2 + 2 + 8 + 3 + 6 + 8 + 1).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 72283681.

It is not an unprimeable number, because it can be changed into a prime (72283691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 976770 + ... + 976843.

It is an arithmetic number, because the mean of its divisors is an integer number (18559333).

Almost surely, 2^72283681 is an apocalyptic number.

72283681 is the 4545-th centered heptagonal number.

It is an amenable number.

72283681 is a deficient number, since it is larger than the sum of its proper divisors (1953651).

72283681 is a wasteful number, since it uses less digits than its factorization.

72283681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1953650.

The product of its digits is 32256, while the sum is 37.

The square root of 72283681 is about 8501.9810044483. The cubic root of 72283681 is about 416.5624192179.

The spelling of 72283681 in words is "seventy-two million, two hundred eighty-three thousand, six hundred eighty-one".