72843721 has 2 divisors, whose sum is σ = 72843722. Its totient is φ = 72843720.

The previous prime is 72843671. The next prime is 72843733. The reversal of 72843721 is 12734827.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45751696 + 27092025 = 6764^2 + 5205^2 .

It is a cyclic number.

It is not a de Polignac number, because 72843721 - 2¹⁵ = 72810953 is a prime.

It is not a weakly prime, because it can be changed into another prime (72844721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36421860 + 36421861.

It is an arithmetic number, because the mean of its divisors is an integer number (36421861).

Almost surely, 2^72843721 is an apocalyptic number.

It is an amenable number.

72843721 is a deficient number, since it is larger than the sum of its proper divisors (1).

72843721 is an equidigital number, since it uses as much as digits as its factorization.

72843721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18816, while the sum is 34.

The square root of 72843721 is about 8534.8533086398. The cubic root of 72843721 is about 417.6354677705.

The spelling of 72843721 in words is "seventy-two million, eight hundred forty-three thousand, seven hundred twenty-one".