72069281 has 4 divisors (see below), whose sum is σ = 75202752. Its totient is φ = 68935812.

The previous prime is 72069271. The next prime is 72069289. The reversal of 72069281 is 18296027.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18296027 = 43 ⋅425489.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72069281 is a prime.

It is a super-2 number, since 2×72069281² = 10387962527713922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72069289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1566701 + ... + 1566746.

It is an arithmetic number, because the mean of its divisors is an integer number (18800688).

Almost surely, 2^72069281 is an apocalyptic number.

It is an amenable number.

72069281 is a deficient number, since it is larger than the sum of its proper divisors (3133471).

72069281 is a wasteful number, since it uses less digits than its factorization.

72069281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3133470.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 72069281 is about 8489.3628147229. The cubic root of 72069281 is about 416.1501572857.

The spelling of 72069281 in words is "seventy-two million, sixty-nine thousand, two hundred eighty-one".