71621591 has 2 divisors, whose sum is σ = 71621592. Its totient is φ = 71621590.

The previous prime is 71621587. The next prime is 71621623. The reversal of 71621591 is 19512617.

It is an a-pointer prime, because the next prime (71621623) can be obtained adding 71621591 to its sum of digits (32).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 71621591 - 2² = 71621587 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71621581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35810795 + 35810796.

It is an arithmetic number, because the mean of its divisors is an integer number (35810796).

Almost surely, 2^71621591 is an apocalyptic number.

71621591 is a deficient number, since it is larger than the sum of its proper divisors (1).

71621591 is an equidigital number, since it uses as much as digits as its factorization.

71621591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3780, while the sum is 32.

The square root of 71621591 is about 8462.9540350873. The cubic root of 71621591 is about 415.2866669858.

The spelling of 71621591 in words is "seventy-one million, six hundred twenty-one thousand, five hundred ninety-one".