71620021021 has 8 divisors (see below), whose sum is σ = 77682548664. Its totient is φ = 65763002880.

The previous prime is 71620021001. The next prime is 71620021051. The reversal of 71620021021 is 12012002617.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1116495396 + 70503525625 = 33414^2 + 265525^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 71620021021 - 2⁹ = 71620020509 is a prime.

It is a super-2 number, since 2×71620021021² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 71620020983 and 71620021001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71620021001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51376650 + ... + 51378043.

It is an arithmetic number, because the mean of its divisors is an integer number (9710318583).

Almost surely, 2^71620021021 is an apocalyptic number.

It is an amenable number.

71620021021 is a deficient number, since it is larger than the sum of its proper divisors (6062527643).

71620021021 is a wasteful number, since it uses less digits than its factorization.

71620021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102754751.

The product of its (nonzero) digits is 336, while the sum is 22.

Adding to 71620021021 its reverse (12012002617), we get a palindrome (83632023638).

The spelling of 71620021021 in words is "seventy-one billion, six hundred twenty million, twenty-one thousand, twenty-one".