71707921 has 4 divisors (see below), whose sum is σ = 75926052. Its totient is φ = 67489792.

The previous prime is 71707913. The next prime is 71707943. The reversal of 71707921 is 12970717.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12970717 = 3169 ⋅4093.

It can be written as a sum of positive squares in 2 ways, for example, as 32080896 + 39627025 = 5664^2 + 6295^2 .

It is a cyclic number.

It is not a de Polignac number, because 71707921 - 2³ = 71707913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71707901) 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, 2109040 + ... + 2109073.

It is an arithmetic number, because the mean of its divisors is an integer number (18981513).

Almost surely, 2^71707921 is an apocalyptic number.

It is an amenable number.

71707921 is a deficient number, since it is larger than the sum of its proper divisors (4218131).

71707921 is a wasteful number, since it uses less digits than its factorization.

71707921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4218130.

The product of its (nonzero) digits is 6174, while the sum is 34.

The square root of 71707921 is about 8468.0529639345. The cubic root of 71707921 is about 415.4534570200.

The spelling of 71707921 in words is "seventy-one million, seven hundred seven thousand, nine hundred twenty-one".