71445421 has 4 divisors (see below), whose sum is σ = 73750144. Its totient is φ = 69140700.

The previous prime is 71445371. The next prime is 71445443. The reversal of 71445421 is 12454417.

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: 12454417 = 53 ⋅234989.

It is a cyclic number.

It is not a de Polignac number, because 71445421 - 2⁹ = 71444909 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 71445421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75445421) 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, 1152315 + ... + 1152376.

It is an arithmetic number, because the mean of its divisors is an integer number (18437536).

Almost surely, 2^71445421 is an apocalyptic number.

It is an amenable number.

71445421 is a deficient number, since it is larger than the sum of its proper divisors (2304723).

71445421 is a wasteful number, since it uses less digits than its factorization.

71445421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2304722.

The product of its digits is 4480, while the sum is 28.

The square root of 71445421 is about 8452.5393225941. The cubic root of 71445421 is about 414.9458893015.

Adding to 71445421 its reverse (12454417), we get a palindrome (83899838).

The spelling of 71445421 in words is "seventy-one million, four hundred forty-five thousand, four hundred twenty-one".