20520001211221 has 4 divisors (see below), whose sum is σ = 20520054683712. Its totient is φ = 20519947738732.

The previous prime is 20520001211191. The next prime is 20520001211251. The reversal of 20520001211221 is 12211210002502.

It is a happy number.

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 (20520001211191) and next prime (20520001211251).

It is a cyclic number.

It is not a de Polignac number, because 20520001211221 - 2⁵ = 20520001211189 is a prime.

It is a super-2 number, since 2×20520001211221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20520001211251) 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, 26156431 + ... + 26929516.

It is an arithmetic number, because the mean of its divisors is an integer number (5130013670928).

Almost surely, 2^{20520001211221} is an apocalyptic number.

It is an amenable number.

20520001211221 is a deficient number, since it is larger than the sum of its proper divisors (53472491).

20520001211221 is an equidigital number, since it uses as much as digits as its factorization.

20520001211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53472490.

The product of its (nonzero) digits is 160, while the sum is 19.

Adding to 20520001211221 its reverse (12211210002502), we get a palindrome (32731211213723).

The spelling of 20520001211221 in words is "twenty trillion, five hundred twenty billion, one million, two hundred eleven thousand, two hundred twenty-one".