21634337 has 2 divisors, whose sum is σ = 21634338. Its totient is φ = 21634336.

The previous prime is 21634309. The next prime is 21634399. The reversal of 21634337 is 73343612.

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., 12967201 + 8667136 = 3601^2 + 2944^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21634337 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21634037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10817168 + 10817169.

It is an arithmetic number, because the mean of its divisors is an integer number (10817169).

Almost surely, 2^21634337 is an apocalyptic number.

It is an amenable number.

21634337 is a deficient number, since it is larger than the sum of its proper divisors (1).

21634337 is an equidigital number, since it uses as much as digits as its factorization.

21634337 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 29.

The square root of 21634337 is about 4651.2726215521. The cubic root of 21634337 is about 278.6428243288.

Adding to 21634337 its reverse (73343612), we get a palindrome (94977949).

The spelling of 21634337 in words is "twenty-one million, six hundred thirty-four thousand, three hundred thirty-seven".