71983921 has 2 divisors, whose sum is σ = 71983922. Its totient is φ = 71983920.

The previous prime is 71983903. The next prime is 71983937. The reversal of 71983921 is 12938917.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53802225 + 18181696 = 7335^2 + 4264^2 .

It is an emirp because it is prime and its reverse (12938917) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71983921 - 2¹⁷ = 71852849 is a prime.

It is not a weakly prime, because it can be changed into another prime (71980921) 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, 35991960 + 35991961.

It is an arithmetic number, because the mean of its divisors is an integer number (35991961).

Almost surely, 2^71983921 is an apocalyptic number.

It is an amenable number.

71983921 is a deficient number, since it is larger than the sum of its proper divisors (1).

71983921 is an equidigital number, since it uses as much as digits as its factorization.

71983921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 40.

The square root of 71983921 is about 8484.3338571746. Note that the first 3 decimals coincide. The cubic root of 71983921 is about 415.9857940939.

The spelling of 71983921 in words is "seventy-one million, nine hundred eighty-three thousand, nine hundred twenty-one".