21200137 has 4 divisors (see below), whose sum is σ = 24228736. Its totient is φ = 18171540.

The previous prime is 21200129. The next prime is 21200147. The reversal of 21200137 is 73100212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21200137 - 2³ = 21200129 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21200137.

It is not an unprimeable number, because it can be changed into a prime (21200117) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1514289 + ... + 1514302.

It is an arithmetic number, because the mean of its divisors is an integer number (6057184).

Almost surely, 2^21200137 is an apocalyptic number.

It is an amenable number.

21200137 is a deficient number, since it is larger than the sum of its proper divisors (3028599).

21200137 is an equidigital number, since it uses as much as digits as its factorization.

21200137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3028598.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 21200137 is about 4604.3606505138. The cubic root of 21200137 is about 276.7660969049.

Adding to 21200137 its reverse (73100212), we get a palindrome (94300349).

The spelling of 21200137 in words is "twenty-one million, two hundred thousand, one hundred thirty-seven".