20131212021 has 4 divisors (see below), whose sum is σ = 26841616032. Its totient is φ = 13420808012.

The previous prime is 20131211983. The next prime is 20131212029. The reversal of 20131212021 is 12021213102.

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 20131212021 - 2¹⁵ = 20131179253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20131212029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3355202001 + ... + 3355202006.

It is an arithmetic number, because the mean of its divisors is an integer number (6710404008).

Almost surely, 2^20131212021 is an apocalyptic number.

It is an amenable number.

20131212021 is a deficient number, since it is larger than the sum of its proper divisors (6710404011).

20131212021 is an equidigital number, since it uses as much as digits as its factorization.

20131212021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6710404010.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 20131212021 its reverse (12021213102), we get a palindrome (32152425123).

The spelling of 20131212021 in words is "twenty billion, one hundred thirty-one million, two hundred twelve thousand, twenty-one".