71855221 has 4 divisors (see below), whose sum is σ = 73797292. Its totient is φ = 69913152.

The previous prime is 71855213. The next prime is 71855237. The reversal of 71855221 is 12255817.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 59074596 + 12780625 = 7686^2 + 3575^2 .

It is a cyclic number.

It is not a de Polignac number, because 71855221 - 2³ = 71855213 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 (71855281) 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, 970980 + ... + 971053.

It is an arithmetic number, because the mean of its divisors is an integer number (18449323).

Almost surely, 2^71855221 is an apocalyptic number.

It is an amenable number.

71855221 is a deficient number, since it is larger than the sum of its proper divisors (1942071).

71855221 is a wasteful number, since it uses less digits than its factorization.

71855221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1942070.

The product of its digits is 5600, while the sum is 31.

The square root of 71855221 is about 8476.7458968640. The cubic root of 71855221 is about 415.7377326326.

The spelling of 71855221 in words is "seventy-one million, eight hundred fifty-five thousand, two hundred twenty-one".