20101421 has 2 divisors, whose sum is σ = 20101422. Its totient is φ = 20101420.

The previous prime is 20101399. The next prime is 20101427. The reversal of 20101421 is 12410102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19758025 + 343396 = 4445^2 + 586^2 .

It is a cyclic number.

It is not a de Polignac number, because 20101421 - 2¹⁰ = 20100397 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20101427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10050710 + 10050711.

It is an arithmetic number, because the mean of its divisors is an integer number (10050711).

Almost surely, 2^20101421 is an apocalyptic number.

It is an amenable number.

20101421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20101421 is an equidigital number, since it uses as much as digits as its factorization.

20101421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 20101421 is about 4483.4608284226. The cubic root of 20101421 is about 271.8998198330.

Adding to 20101421 its reverse (12410102), we get a palindrome (32511523).

The spelling of 20101421 in words is "twenty million, one hundred one thousand, four hundred twenty-one".