21400101421 has 2 divisors, whose sum is σ = 21400101422. Its totient is φ = 21400101420.

The previous prime is 21400101419. The next prime is 21400101427. The reversal of 21400101421 is 12410100412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12675607396 + 8724494025 = 112586^2 + 93405^2 .

It is a cyclic number.

It is not a de Polignac number, because 21400101421 - 2¹ = 21400101419 is a prime.

Together with 21400101419, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21400101395 and 21400101404.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21400101427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700050710 + 10700050711.

It is an arithmetic number, because the mean of its divisors is an integer number (10700050711).

Almost surely, 2^21400101421 is an apocalyptic number.

It is an amenable number.

21400101421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21400101421 is an equidigital number, since it uses as much as digits as its factorization.

21400101421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21400101421 its reverse (12410100412), we get a palindrome (33810201833).

The spelling of 21400101421 in words is "twenty-one billion, four hundred million, one hundred one thousand, four hundred twenty-one".