72309121 has 2 divisors, whose sum is σ = 72309122. Its totient is φ = 72309120.

The previous prime is 72309113. The next prime is 72309131. The reversal of 72309121 is 12190327.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48650625 + 23658496 = 6975^2 + 4864^2 .

It is a cyclic number.

It is not a de Polignac number, because 72309121 - 2³ = 72309113 is a prime.

It is not a weakly prime, because it can be changed into another prime (72309131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36154560 + 36154561.

It is an arithmetic number, because the mean of its divisors is an integer number (36154561).

Almost surely, 2^72309121 is an apocalyptic number.

It is an amenable number.

72309121 is a deficient number, since it is larger than the sum of its proper divisors (1).

72309121 is an equidigital number, since it uses as much as digits as its factorization.

72309121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 72309121 is about 8503.4769947357. The cubic root of 72309121 is about 416.6112827364.

Adding to 72309121 its reverse (12190327), we get a palindrome (84499448).

The spelling of 72309121 in words is "seventy-two million, three hundred nine thousand, one hundred twenty-one".