21109037 has 4 divisors (see below), whose sum is σ = 21376320. Its totient is φ = 20841756.

The previous prime is 21109007. The next prime is 21109061. The reversal of 21109037 is 73090112.

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 21109037 - 2²⁰ = 20060461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21109007) 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, 133523 + ... + 133680.

It is an arithmetic number, because the mean of its divisors is an integer number (5344080).

Almost surely, 2^21109037 is an apocalyptic number.

It is an amenable number.

21109037 is a deficient number, since it is larger than the sum of its proper divisors (267283).

21109037 is an equidigital number, since it uses as much as digits as its factorization.

21109037 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267282.

The product of its (nonzero) digits is 378, while the sum is 23.

The square root of 21109037 is about 4594.4572040667. The cubic root of 21109037 is about 276.3690932901.

Adding to 21109037 its reverse (73090112), we get a palindrome (94199149).

The spelling of 21109037 in words is "twenty-one million, one hundred nine thousand, thirty-seven".