212521421 has 4 divisors (see below), whose sum is σ = 242881632. Its totient is φ = 182161212.

The previous prime is 212521411. The next prime is 212521423. The reversal of 212521421 is 124125212.

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 212521421 - 2¹⁰ = 212520397 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 212521393 and 212521402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212521423) 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, 15180095 + ... + 15180108.

It is an arithmetic number, because the mean of its divisors is an integer number (60720408).

Almost surely, 2^212521421 is an apocalyptic number.

It is an amenable number.

212521421 is a deficient number, since it is larger than the sum of its proper divisors (30360211).

212521421 is an equidigital number, since it uses as much as digits as its factorization.

212521421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30360210.

The product of its digits is 320, while the sum is 20.

The square root of 212521421 is about 14578.1144528365. The cubic root of 212521421 is about 596.7616467436.

Adding to 212521421 its reverse (124125212), we get a palindrome (336646633).

The spelling of 212521421 in words is "two hundred twelve million, five hundred twenty-one thousand, four hundred twenty-one".