21614909 has 4 divisors (see below), whose sum is σ = 21829020. Its totient is φ = 21400800.

The previous prime is 21614899. The next prime is 21614911. The reversal of 21614909 is 90941612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11868025 + 9746884 = 3445^2 + 3122^2 .

It is a cyclic number.

It is not a de Polignac number, because 21614909 - 2⁴ = 21614893 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21614959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106904 + ... + 107105.

It is an arithmetic number, because the mean of its divisors is an integer number (5457255).

Almost surely, 2^21614909 is an apocalyptic number.

It is an amenable number.

21614909 is a deficient number, since it is larger than the sum of its proper divisors (214111).

21614909 is a wasteful number, since it uses less digits than its factorization.

21614909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214110.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 21614909 is about 4649.1836917893. The cubic root of 21614909 is about 278.5593906949.

The spelling of 21614909 in words is "twenty-one million, six hundred fourteen thousand, nine hundred nine".