212730720521 has 32 divisors (see below), whose sum is σ = 247404879360. Its totient is φ = 181141228800.

The previous prime is 212730720511. The next prime is 212730720529. The reversal of 212730720521 is 125027037212.

It is a cyclic number.

It is not a de Polignac number, because 212730720521 - 2³⁴ = 195550851337 is a prime.

It is a super-2 number, since 2×212730720521² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212730720529) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1075715 + ... + 1258023.

It is an arithmetic number, because the mean of its divisors is an integer number (7731402480).

Almost surely, 2^212730720521 is an apocalyptic number.

It is an amenable number.

212730720521 is a deficient number, since it is larger than the sum of its proper divisors (34674158839).

212730720521 is a wasteful number, since it uses less digits than its factorization.

212730720521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182465.

The product of its (nonzero) digits is 11760, while the sum is 32.

Adding to 212730720521 its reverse (125027037212), we get a palindrome (337757757733).

The spelling of 212730720521 in words is "two hundred twelve billion, seven hundred thirty million, seven hundred twenty thousand, five hundred twenty-one".