21212131654245 has 24 divisors (see below), whose sum is σ = 39480538917024. Its totient is φ = 9696974470176.

The previous prime is 21212131654243. The next prime is 21212131654247. The reversal of 21212131654245 is 54245613121212.

It is an interprime number because it is at equal distance from previous prime (21212131654243) and next prime (21212131654247).

It is not a de Polignac number, because 21212131654245 - 2¹ = 21212131654243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212131654243) 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 23 ways as a sum of consecutive naturals, for example, 14430020799 + ... + 14430022268.

It is an arithmetic number, because the mean of its divisors is an integer number (1645022454876).

Almost surely, 2^{21212131654245} is an apocalyptic number.

It is an amenable number.

21212131654245 is a deficient number, since it is larger than the sum of its proper divisors (18268407262779).

21212131654245 is a wasteful number, since it uses less digits than its factorization.

21212131654245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28860043089 (or 28860043082 counting only the distinct ones).

The product of its digits is 115200, while the sum is 39.

Adding to 21212131654245 its reverse (54245613121212), we get a palindrome (75457744775457).

The spelling of 21212131654245 in words is "twenty-one trillion, two hundred twelve billion, one hundred thirty-one million, six hundred fifty-four thousand, two hundred forty-five".