71845421 has 4 divisors (see below), whose sum is σ = 73063200. Its totient is φ = 70627644.

The previous prime is 71845393. The next prime is 71845429. The reversal of 71845421 is 12454817.

It is a happy number.

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: 12454817 = 139 ⋅89603.

It is a cyclic number.

It is not a de Polignac number, because 71845421 - 2⁶ = 71845357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71845429) 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, 608801 + ... + 608918.

It is an arithmetic number, because the mean of its divisors is an integer number (18265800).

Almost surely, 2^71845421 is an apocalyptic number.

It is an amenable number.

71845421 is a deficient number, since it is larger than the sum of its proper divisors (1217779).

71845421 is a wasteful number, since it uses less digits than its factorization.

71845421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1217778.

The product of its digits is 8960, while the sum is 32.

The square root of 71845421 is about 8476.1678251436. The cubic root of 71845421 is about 415.7188315935.

The spelling of 71845421 in words is "seventy-one million, eight hundred forty-five thousand, four hundred twenty-one".