71655601021 has 2 divisors, whose sum is σ = 71655601022. Its totient is φ = 71655601020.

The previous prime is 71655600983. The next prime is 71655601063. The reversal of 71655601021 is 12010655617.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71043038521 + 612562500 = 266539^2 + 24750^2 .

It is a cyclic number.

It is not a de Polignac number, because 71655601021 - 2⁷ = 71655600893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71655607021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35827800510 + 35827800511.

It is an arithmetic number, because the mean of its divisors is an integer number (35827800511).

Almost surely, 2^71655601021 is an apocalyptic number.

It is an amenable number.

71655601021 is a deficient number, since it is larger than the sum of its proper divisors (1).

71655601021 is an equidigital number, since it uses as much as digits as its factorization.

71655601021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12600, while the sum is 34.

The spelling of 71655601021 in words is "seventy-one billion, six hundred fifty-five million, six hundred one thousand, twenty-one".