71716781 has 2 divisors, whose sum is σ = 71716782. Its totient is φ = 71716780.

The previous prime is 71716763. The next prime is 71716787. The reversal of 71716781 is 18761717.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55636681 + 16080100 = 7459^2 + 4010^2 .

It is a cyclic number.

It is not a de Polignac number, because 71716781 - 2⁶ = 71716717 is a prime.

It is a super-2 number, since 2×71716781² = 10286593354003922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71716787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35858390 + 35858391.

It is an arithmetic number, because the mean of its divisors is an integer number (35858391).

Almost surely, 2^71716781 is an apocalyptic number.

It is an amenable number.

71716781 is a deficient number, since it is larger than the sum of its proper divisors (1).

71716781 is an equidigital number, since it uses as much as digits as its factorization.

71716781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16464, while the sum is 38.

The square root of 71716781 is about 8468.5760904653. The cubic root of 71716781 is about 415.4705670128.

The spelling of 71716781 in words is "seventy-one million, seven hundred sixteen thousand, seven hundred eighty-one".