212500021 has 4 divisors (see below), whose sum is σ = 214563232. Its totient is φ = 210436812.

The previous prime is 212499997. The next prime is 212500039. The reversal of 212500021 is 120005212.

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.

It is a cyclic number.

It is not a de Polignac number, because 212500021 - 2⁷ = 212499893 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212499974 and 212500010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212500091) 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, 1031451 + ... + 1031656.

It is an arithmetic number, because the mean of its divisors is an integer number (53640808).

Almost surely, 2^212500021 is an apocalyptic number.

It is an amenable number.

212500021 is a deficient number, since it is larger than the sum of its proper divisors (2063211).

212500021 is a wasteful number, since it uses less digits than its factorization.

212500021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2063210.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 212500021 is about 14577.3804574073. The cubic root of 212500021 is about 596.7416156210.

Adding to 212500021 its reverse (120005212), we get a palindrome (332505233).

The spelling of 212500021 in words is "two hundred twelve million, five hundred thousand, twenty-one".