72278281 has 2 divisors, whose sum is σ = 72278282. Its totient is φ = 72278280.

The previous prime is 72278263. The next prime is 72278291. The reversal of 72278281 is 18287227.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60140025 + 12138256 = 7755^2 + 3484^2 .

It is a cyclic number.

It is not a de Polignac number, because 72278281 - 2⁹ = 72277769 is a prime.

It is a super-2 number, since 2×72278281² = 10448299808629922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 72278281.

It is not a weakly prime, because it can be changed into another prime (72278201) 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 as a sum of consecutive naturals, namely, 36139140 + 36139141.

It is an arithmetic number, because the mean of its divisors is an integer number (36139141).

Almost surely, 2^72278281 is an apocalyptic number.

It is an amenable number.

72278281 is a deficient number, since it is larger than the sum of its proper divisors (1).

72278281 is an equidigital number, since it uses as much as digits as its factorization.

72278281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25088, while the sum is 37.

The square root of 72278281 is about 8501.6634254715. The cubic root of 72278281 is about 416.5520457696.

It can be divided in two parts, 722 and 78281, that added together give a triangular number (79003 = T₃₉₇).

The spelling of 72278281 in words is "seventy-two million, two hundred seventy-eight thousand, two hundred eighty-one".