21337237 has 2 divisors, whose sum is σ = 21337238. Its totient is φ = 21337236.

The previous prime is 21337231. The next prime is 21337241. The reversal of 21337237 is 73273312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19280881 + 2056356 = 4391^2 + 1434^2 .

It is a cyclic number.

It is not a de Polignac number, because 21337237 - 2⁷ = 21337109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21337231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10668618 + 10668619.

It is an arithmetic number, because the mean of its divisors is an integer number (10668619).

Almost surely, 2^21337237 is an apocalyptic number.

It is an amenable number.

21337237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21337237 is an equidigital number, since it uses as much as digits as its factorization.

21337237 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5292, while the sum is 28.

The square root of 21337237 is about 4619.2247184998. The cubic root of 21337237 is about 277.3614252791.

The spelling of 21337237 in words is "twenty-one million, three hundred thirty-seven thousand, two hundred thirty-seven".