71660737021 has 2 divisors, whose sum is σ = 71660737022. Its totient is φ = 71660737020.

The previous prime is 71660737019. The next prime is 71660737061. The reversal of 71660737021 is 12073706617.

It is an a-pointer prime, because the next prime (71660737061) can be obtained adding 71660737021 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70974820921 + 685916100 = 266411^2 + 26190^2 .

It is a cyclic number.

It is not a de Polignac number, because 71660737021 - 2¹ = 71660737019 is a prime.

It is a super-2 number, since 2×71660737021² (a number of 23 digits) contains 22 as substring.

Together with 71660737019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71660737061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35830368510 + 35830368511.

It is an arithmetic number, because the mean of its divisors is an integer number (35830368511).

Almost surely, 2^71660737021 is an apocalyptic number.

It is an amenable number.

71660737021 is a deficient number, since it is larger than the sum of its proper divisors (1).

71660737021 is an equidigital number, since it uses as much as digits as its factorization.

71660737021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 74088, while the sum is 40.

The spelling of 71660737021 in words is "seventy-one billion, six hundred sixty million, seven hundred thirty-seven thousand, twenty-one".