21421400237 has 2 divisors, whose sum is σ = 21421400238. Its totient is φ = 21421400236.

The previous prime is 21421400201. The next prime is 21421400243. The reversal of 21421400237 is 73200412412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19013927881 + 2407472356 = 137891^2 + 49066^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21421400237 is a prime.

It is a super-2 number, since 2×21421400237² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21421400837) 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, 10710700118 + 10710700119.

It is an arithmetic number, because the mean of its divisors is an integer number (10710700119).

Almost surely, 2^21421400237 is an apocalyptic number.

It is an amenable number.

21421400237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21421400237 is an equidigital number, since it uses as much as digits as its factorization.

21421400237 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2688, while the sum is 26.

Adding to 21421400237 its reverse (73200412412), we get a palindrome (94621812649).

The spelling of 21421400237 in words is "twenty-one billion, four hundred twenty-one million, four hundred thousand, two hundred thirty-seven".