71709021 has 12 divisors (see below), whose sum is σ = 109031520. Its totient is φ = 45289800.

The previous prime is 71709017. The next prime is 71709023. The reversal of 71709021 is 12090717.

It is not a de Polignac number, because 71709021 - 2² = 71709017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71709023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 209505 + ... + 209846.

It is an arithmetic number, because the mean of its divisors is an integer number (9085960).

Almost surely, 2^71709021 is an apocalyptic number.

It is an amenable number.

71709021 is a deficient number, since it is larger than the sum of its proper divisors (37322499).

71709021 is a wasteful number, since it uses less digits than its factorization.

71709021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419376 (or 419373 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 27.

The square root of 71709021 is about 8468.1179136807. The cubic root of 71709021 is about 415.4555813621.

Adding to 71709021 its reverse (12090717), we get a palindrome (83799738).

The spelling of 71709021 in words is "seventy-one million, seven hundred nine thousand, twenty-one".