21739105 has 4 divisors (see below), whose sum is σ = 26086932. Its totient is φ = 17391280.

The previous prime is 21739103. The next prime is 21739129. The reversal of 21739105 is 50193712.

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 5035536 + 16703569 = 2244^2 + 4087^2 .

It is not a de Polignac number, because 21739105 - 2¹ = 21739103 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21739103) 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, 2173906 + ... + 2173915.

It is an arithmetic number, because the mean of its divisors is an integer number (6521733).

Almost surely, 2^21739105 is an apocalyptic number.

It is an amenable number.

21739105 is a deficient number, since it is larger than the sum of its proper divisors (4347827).

21739105 is an equidigital number, since it uses as much as digits as its factorization.

21739105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4347826.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 21739105 is about 4662.5213136242. The cubic root of 21739105 is about 279.0918921539.

The spelling of 21739105 in words is "twenty-one million, seven hundred thirty-nine thousand, one hundred five".