71638121 has 2 divisors, whose sum is σ = 71638122. Its totient is φ = 71638120.

The previous prime is 71638103. The next prime is 71638159. The reversal of 71638121 is 12183617.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70224400 + 1413721 = 8380^2 + 1189^2 .

It is a cyclic number.

It is not a de Polignac number, because 71638121 - 2⁶ = 71638057 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (71638181) 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, 35819060 + 35819061.

It is an arithmetic number, because the mean of its divisors is an integer number (35819061).

Almost surely, 2^71638121 is an apocalyptic number.

It is an amenable number.

71638121 is a deficient number, since it is larger than the sum of its proper divisors (1).

71638121 is an equidigital number, since it uses as much as digits as its factorization.

71638121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 29.

The square root of 71638121 is about 8463.9305880897. The cubic root of 71638121 is about 415.3186134071.

The spelling of 71638121 in words is "seventy-one million, six hundred thirty-eight thousand, one hundred twenty-one".