71380781 has 2 divisors, whose sum is σ = 71380782. Its totient is φ = 71380780.

The previous prime is 71380763. The next prime is 71380801. The reversal of 71380781 is 18708317.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38502025 + 32878756 = 6205^2 + 5734^2 .

It is a cyclic number.

It is not a de Polignac number, because 71380781 - 2⁶ = 71380717 is a prime.

It is a super-2 number, since 2×71380781² = 10190431792339922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71380741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35690390 + 35690391.

It is an arithmetic number, because the mean of its divisors is an integer number (35690391).

Almost surely, 2^71380781 is an apocalyptic number.

It is an amenable number.

71380781 is a deficient number, since it is larger than the sum of its proper divisors (1).

71380781 is an equidigital number, since it uses as much as digits as its factorization.

71380781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9408, while the sum is 35.

The square root of 71380781 is about 8448.7147543280. The cubic root of 71380781 is about 414.8207112516.

The spelling of 71380781 in words is "seventy-one million, three hundred eighty thousand, seven hundred eighty-one".