71755921 has 2 divisors, whose sum is σ = 71755922. Its totient is φ = 71755920.

The previous prime is 71755919. The next prime is 71755961. The reversal of 71755921 is 12955717.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69906321 + 1849600 = 8361^2 + 1360^2 .

It is a cyclic number.

It is not a de Polignac number, because 71755921 - 2¹ = 71755919 is a prime.

Together with 71755919, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (71755961) 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, 35877960 + 35877961.

It is an arithmetic number, because the mean of its divisors is an integer number (35877961).

Almost surely, 2^71755921 is an apocalyptic number.

It is an amenable number.

71755921 is a deficient number, since it is larger than the sum of its proper divisors (1).

71755921 is an equidigital number, since it uses as much as digits as its factorization.

71755921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22050, while the sum is 37.

The square root of 71755921 is about 8470.8866714176. The cubic root of 71755921 is about 415.5461353822.

The spelling of 71755921 in words is "seventy-one million, seven hundred fifty-five thousand, nine hundred twenty-one".