72645257 has 2 divisors, whose sum is σ = 72645258. Its totient is φ = 72645256.

The previous prime is 72645241. The next prime is 72645259. The reversal of 72645257 is 75254627.

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., 68740681 + 3904576 = 8291^2 + 1976^2 .

It is a cyclic number.

It is not a de Polignac number, because 72645257 - 2⁴ = 72645241 is a prime.

Together with 72645259, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 72645257.

It is not a weakly prime, because it can be changed into another prime (72645259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36322628 + 36322629.

It is an arithmetic number, because the mean of its divisors is an integer number (36322629).

Almost surely, 2^72645257 is an apocalyptic number.

It is an amenable number.

72645257 is a deficient number, since it is larger than the sum of its proper divisors (1).

72645257 is an equidigital number, since it uses as much as digits as its factorization.

72645257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 117600, while the sum is 38.

The square root of 72645257 is about 8523.2186995290. The cubic root of 72645257 is about 417.2558377310.

It can be divided in two parts, 7264 and 5257, that added together give a palindrome (12521).

The spelling of 72645257 in words is "seventy-two million, six hundred forty-five thousand, two hundred fifty-seven".