71016821 has 4 divisors (see below), whose sum is σ = 71035392. Its totient is φ = 70998252.

The previous prime is 71016811. The next prime is 71016823. The reversal of 71016821 is 12861017.

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: 12861017 = 13 ⋅989309.

It is a cyclic number.

It is not a de Polignac number, because 71016821 - 2¹⁰ = 71015797 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71016823) 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, 1205 + ... + 11978.

It is an arithmetic number, because the mean of its divisors is an integer number (17758848).

Almost surely, 2^71016821 is an apocalyptic number.

71016821 is the 4505-th centered heptagonal number.

It is an amenable number.

71016821 is a deficient number, since it is larger than the sum of its proper divisors (18571).

71016821 is a wasteful number, since it uses less digits than its factorization.

71016821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18570.

The product of its (nonzero) digits is 672, while the sum is 26.

The square root of 71016821 is about 8427.1478567781. The cubic root of 71016821 is about 414.1144731561.

Adding to 71016821 its reverse (12861017), we get a palindrome (83877838).

The spelling of 71016821 in words is "seventy-one million, sixteen thousand, eight hundred twenty-one".