71691121 has 4 divisors (see below), whose sum is σ = 73216512. Its totient is φ = 70165732.

The previous prime is 71691101. The next prime is 71691131. The reversal of 71691121 is 12119617.

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: 12119617 = 631 ⋅19207.

It is a cyclic number.

It is not a de Polignac number, because 71691121 - 2¹⁹ = 71166833 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 71691121.

It is not an unprimeable number, because it can be changed into a prime (71691101) 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, 762625 + ... + 762718.

It is an arithmetic number, because the mean of its divisors is an integer number (18304128).

Almost surely, 2^71691121 is an apocalyptic number.

It is an amenable number.

71691121 is a deficient number, since it is larger than the sum of its proper divisors (1525391).

71691121 is a wasteful number, since it uses less digits than its factorization.

71691121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1525390.

The product of its digits is 756, while the sum is 28.

The square root of 71691121 is about 8467.0609422633. The cubic root of 71691121 is about 415.4210098225.

The spelling of 71691121 in words is "seventy-one million, six hundred ninety-one thousand, one hundred twenty-one".