21204240037 has 2 divisors, whose sum is σ = 21204240038. Its totient is φ = 21204240036.

The previous prime is 21204240011. The next prime is 21204240059. The reversal of 21204240037 is 73004240212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16147039041 + 5057200996 = 127071^2 + 71114^2 .

It is a cyclic number.

It is not a de Polignac number, because 21204240037 - 2²³ = 21195851429 is a prime.

It is a super-2 number, since 2×21204240037² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21204239993 and 21204240020.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21204240637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602120018 + 10602120019.

It is an arithmetic number, because the mean of its divisors is an integer number (10602120019).

Almost surely, 2^21204240037 is an apocalyptic number.

It is an amenable number.

21204240037 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204240037 is an equidigital number, since it uses as much as digits as its factorization.

21204240037 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 25.

Adding to 21204240037 its reverse (73004240212), we get a palindrome (94208480249).

The spelling of 21204240037 in words is "twenty-one billion, two hundred four million, two hundred forty thousand, thirty-seven".