2121205436 has 48 divisors (see below), whose sum is σ = 4313831424. Its totient is φ = 893889216.

The previous prime is 2121205423. The next prime is 2121205439. The reversal of 2121205436 is 6345021212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121205439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 516206 + ... + 520298.

It is an arithmetic number, because the mean of its divisors is an integer number (89871488).

Almost surely, 2^2121205436 is an apocalyptic number.

It is an amenable number.

2121205436 is an abundant number, since it is smaller than the sum of its proper divisors (2192625988).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2121205436 is a wasteful number, since it uses less digits than its factorization.

2121205436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4410 (or 4408 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 2121205436 is about 46056.5460711070. The cubic root of 2121205436 is about 1284.8750929072.

Adding to 2121205436 its reverse (6345021212), we get a palindrome (8466226648).

The spelling of 2121205436 in words is "two billion, one hundred twenty-one million, two hundred five thousand, four hundred thirty-six".