71831621 has 2 divisors, whose sum is σ = 71831622. Its totient is φ = 71831620.

The previous prime is 71831611. The next prime is 71831657. The reversal of 71831621 is 12613817.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53436100 + 18395521 = 7310^2 + 4289^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71831621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71831611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35915810 + 35915811.

It is an arithmetic number, because the mean of its divisors is an integer number (35915811).

Almost surely, 2^71831621 is an apocalyptic number.

It is an amenable number.

71831621 is a deficient number, since it is larger than the sum of its proper divisors (1).

71831621 is an equidigital number, since it uses as much as digits as its factorization.

71831621 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 71831621 is about 8475.3537389303. The cubic root of 71831621 is about 415.6922129302.

The spelling of 71831621 in words is "seventy-one million, eight hundred thirty-one thousand, six hundred twenty-one".