71500421 has 4 divisors (see below), whose sum is σ = 71587500. Its totient is φ = 71413344.

The previous prime is 71500409. The next prime is 71500423. The reversal of 71500421 is 12400517.

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 59459521 + 12040900 = 7711^2 + 3470^2 .

It is a cyclic number.

It is not a de Polignac number, because 71500421 - 2¹⁰ = 71499397 is a prime.

It is a super-2 number, since 2×71500421² = 10224620406354482, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 71500393 and 71500402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71500423) 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, 42296 + ... + 43953.

It is an arithmetic number, because the mean of its divisors is an integer number (17896875).

Almost surely, 2^71500421 is an apocalyptic number.

It is an amenable number.

71500421 is a deficient number, since it is larger than the sum of its proper divisors (87079).

71500421 is an equidigital number, since it uses as much as digits as its factorization.

71500421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87078.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 71500421 is about 8455.7921568591. The cubic root of 71500421 is about 415.0523396511.

Adding to 71500421 its reverse (12400517), we get a palindrome (83900938).

The spelling of 71500421 in words is "seventy-one million, five hundred thousand, four hundred twenty-one".