21311137 has 2 divisors, whose sum is σ = 21311138. Its totient is φ = 21311136.

The previous prime is 21311123. The next prime is 21311161. The reversal of 21311137 is 73111312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20466576 + 844561 = 4524^2 + 919^2 .

It is a cyclic number.

It is not a de Polignac number, because 21311137 - 2²³ = 12922529 is a prime.

It is not a weakly prime, because it can be changed into another prime (21311107) 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, 10655568 + 10655569.

It is an arithmetic number, because the mean of its divisors is an integer number (10655569).

Almost surely, 2^21311137 is an apocalyptic number.

It is an amenable number.

21311137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311137 is an equidigital number, since it uses as much as digits as its factorization.

21311137 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 126, while the sum is 19.

The square root of 21311137 is about 4616.3987046181. The cubic root of 21311137 is about 277.2482883740.

Adding to 21311137 its reverse (73111312), we get a palindrome (94422449).

The spelling of 21311137 in words is "twenty-one million, three hundred eleven thousand, one hundred thirty-seven".