21371109 has 4 divisors (see below), whose sum is σ = 28494816. Its totient is φ = 14247404.

The previous prime is 21371107. The next prime is 21371113. The reversal of 21371109 is 90117312.

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 21371109 - 2¹ = 21371107 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21371101) 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 in 3 ways as a sum of consecutive naturals, for example, 3561849 + ... + 3561854.

It is an arithmetic number, because the mean of its divisors is an integer number (7123704).

Almost surely, 2^21371109 is an apocalyptic number.

It is an amenable number.

21371109 is a deficient number, since it is larger than the sum of its proper divisors (7123707).

21371109 is an equidigital number, since it uses as much as digits as its factorization.

21371109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7123706.

The product of its (nonzero) digits is 378, while the sum is 24.

The square root of 21371109 is about 4622.8896807084. The cubic root of 21371109 is about 277.5081143638.

The spelling of 21371109 in words is "twenty-one million, three hundred seventy-one thousand, one hundred nine".