21212021461 has 2 divisors, whose sum is σ = 21212021462. Its totient is φ = 21212021460.

The previous prime is 21212021459. The next prime is 21212021491. The reversal of 21212021461 is 16412021212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18695092900 + 2516928561 = 136730^2 + 50169^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212021461 - 2¹ = 21212021459 is a prime.

Together with 21212021459, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212021431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606010730 + 10606010731.

It is an arithmetic number, because the mean of its divisors is an integer number (10606010731).

Almost surely, 2^21212021461 is an apocalyptic number.

It is an amenable number.

21212021461 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212021461 is an equidigital number, since it uses as much as digits as its factorization.

21212021461 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 22.

Adding to 21212021461 its reverse (16412021212), we get a palindrome (37624042673).

The spelling of 21212021461 in words is "twenty-one billion, two hundred twelve million, twenty-one thousand, four hundred sixty-one".