102021421 has 2 divisors, whose sum is σ = 102021422. Its totient is φ = 102021420.

The previous prime is 102021419. The next prime is 102021427. The reversal of 102021421 is 124120201.

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., 65853225 + 36168196 = 8115^2 + 6014^2 .

It is a cyclic number.

It is not a de Polignac number, because 102021421 - 2¹ = 102021419 is a prime.

Together with 102021419, 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 (102021427) 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, 51010710 + 51010711.

It is an arithmetic number, because the mean of its divisors is an integer number (51010711).

Almost surely, 2^102021421 is an apocalyptic number.

It is an amenable number.

102021421 is a deficient number, since it is larger than the sum of its proper divisors (1).

102021421 is an equidigital number, since it uses as much as digits as its factorization.

102021421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 102021421 is about 10100.5653802151. The cubic root of 102021421 is about 467.2655783741.

Adding to 102021421 its reverse (124120201), we get a palindrome (226141622).

The spelling of 102021421 in words is "one hundred two million, twenty-one thousand, four hundred twenty-one".