212204501621 has 4 divisors (see below), whose sum is σ = 242519430432. Its totient is φ = 181889572812.

The previous prime is 212204501543. The next prime is 212204501623. The reversal of 212204501621 is 126105402212.

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 a de Polignac number, because none of the positive numbers 2^k-212204501621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212204501623) 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, 15157464395 + ... + 15157464408.

It is an arithmetic number, because the mean of its divisors is an integer number (60629857608).

Almost surely, 2^212204501621 is an apocalyptic number.

It is an amenable number.

212204501621 is a deficient number, since it is larger than the sum of its proper divisors (30314928811).

212204501621 is an equidigital number, since it uses as much as digits as its factorization.

212204501621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30314928810.

The product of its (nonzero) digits is 1920, while the sum is 26.

Adding to 212204501621 its reverse (126105402212), we get a palindrome (338309903833).

The spelling of 212204501621 in words is "two hundred twelve billion, two hundred four million, five hundred one thousand, six hundred twenty-one".