20012121231221 has 4 divisors (see below), whose sum is σ = 22870995692832. Its totient is φ = 17153246769612.

The previous prime is 20012121231203. The next prime is 20012121231239. The reversal of 20012121231221 is 12213212121002.

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 an interprime number because it is at equal distance from previous prime (20012121231203) and next prime (20012121231239).

It is a cyclic number.

It is not a de Polignac number, because 20012121231221 - 2⁴² = 15614074720117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20012121231193 and 20012121231202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20012121230221) 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, 1429437230795 + ... + 1429437230808.

It is an arithmetic number, because the mean of its divisors is an integer number (5717748923208).

Almost surely, 2^{20012121231221} is an apocalyptic number.

It is an amenable number.

20012121231221 is a deficient number, since it is larger than the sum of its proper divisors (2858874461611).

20012121231221 is an equidigital number, since it uses as much as digits as its factorization.

20012121231221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2858874461610.

The product of its (nonzero) digits is 192, while the sum is 20.

Adding to 20012121231221 its reverse (12213212121002), we get a palindrome (32225333352223).

The spelling of 20012121231221 in words is "twenty trillion, twelve billion, one hundred twenty-one million, two hundred thirty-one thousand, two hundred twenty-one".