71706521 has 4 divisors (see below), whose sum is σ = 72716544. Its totient is φ = 70696500.

The previous prime is 71706517. The next prime is 71706529. The reversal of 71706521 is 12560717.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12560717 = 13 ⋅966209.

It is a cyclic number.

It is not a de Polignac number, because 71706521 - 2² = 71706517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71706529) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 504905 + ... + 505046.

It is an arithmetic number, because the mean of its divisors is an integer number (18179136).

Almost surely, 2^71706521 is an apocalyptic number.

71706521 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

It is an amenable number.

71706521 is a deficient number, since it is larger than the sum of its proper divisors (1010023).

71706521 is a wasteful number, since it uses less digits than its factorization.

71706521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1010022.

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 71706521 is about 8467.9702999007. The cubic root of 71706521 is about 415.4507532804.

It can be divided in two parts, 71706 and 521, that added together give a palindrome (72227).

The spelling of 71706521 in words is "seventy-one million, seven hundred six thousand, five hundred twenty-one".