71671700021 has 2 divisors, whose sum is σ = 71671700022. Its totient is φ = 71671700020.

The previous prime is 71671699969. The next prime is 71671700027. The reversal of 71671700021 is 12000717617.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47506997521 + 24164702500 = 217961^2 + 155450^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71671700021 is a prime.

It is a super-2 number, since 2×71671700021² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71671700027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35835850010 + 35835850011.

It is an arithmetic number, because the mean of its divisors is an integer number (35835850011).

Almost surely, 2^71671700021 is an apocalyptic number.

It is an amenable number.

71671700021 is a deficient number, since it is larger than the sum of its proper divisors (1).

71671700021 is an equidigital number, since it uses as much as digits as its factorization.

71671700021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4116, while the sum is 32.

The spelling of 71671700021 in words is "seventy-one billion, six hundred seventy-one million, seven hundred thousand, twenty-one".