72221257 has 2 divisors, whose sum is σ = 72221258. Its totient is φ = 72221256.

The previous prime is 72221249. The next prime is 72221269. The reversal of 72221257 is 75212227.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37222201 + 34999056 = 6101^2 + 5916^2 .

It is an emirp because it is prime and its reverse (75212227) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72221257 - 2³ = 72221249 is a prime.

It is not a weakly prime, because it can be changed into another prime (72221297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36110628 + 36110629.

It is an arithmetic number, because the mean of its divisors is an integer number (36110629).

Almost surely, 2^72221257 is an apocalyptic number.

It is an amenable number.

72221257 is a deficient number, since it is larger than the sum of its proper divisors (1).

72221257 is an equidigital number, since it uses as much as digits as its factorization.

72221257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3920, while the sum is 28.

The square root of 72221257 is about 8498.3090671027. The cubic root of 72221257 is about 416.4424706061.

The spelling of 72221257 in words is "seventy-two million, two hundred twenty-one thousand, two hundred fifty-seven".