72207281 has 4 divisors (see below), whose sum is σ = 75346752. Its totient is φ = 69067812.

The previous prime is 72207257. The next prime is 72207287. The reversal of 72207281 is 18270227.

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: 18270227 = 43 ⋅424889.

It is a cyclic number.

It is not a de Polignac number, because 72207281 - 2⁶ = 72207217 is a prime.

It is a super-2 number, since 2×72207281² = 10427782858825922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (72207287) 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, 1569701 + ... + 1569746.

It is an arithmetic number, because the mean of its divisors is an integer number (18836688).

Almost surely, 2^72207281 is an apocalyptic number.

It is an amenable number.

72207281 is a deficient number, since it is larger than the sum of its proper divisors (3139471).

72207281 is a wasteful number, since it uses less digits than its factorization.

72207281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3139470.

The product of its (nonzero) digits is 3136, while the sum is 29.

The square root of 72207281 is about 8497.4867460915. The cubic root of 72207281 is about 416.4156060527.

The spelling of 72207281 in words is "seventy-two million, two hundred seven thousand, two hundred eighty-one".