21751005 has 16 divisors (see below), whose sum is σ = 35743104. Its totient is φ = 11286720.

The previous prime is 21750997. The next prime is 21751019. The reversal of 21751005 is 50015712.

It is not a de Polignac number, because 21751005 - 2³ = 21750997 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19041 + ... + 20150.

It is an arithmetic number, because the mean of its divisors is an integer number (2233944).

Almost surely, 2^21751005 is an apocalyptic number.

It is an amenable number.

21751005 is a deficient number, since it is larger than the sum of its proper divisors (13992099).

21751005 is a wasteful number, since it uses less digits than its factorization.

21751005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39236.

The product of its (nonzero) digits is 350, while the sum is 21.

The square root of 21751005 is about 4663.7972726095. The cubic root of 21751005 is about 279.1428078914.

Adding to 21751005 its reverse (50015712), we get a palindrome (71766717).

The spelling of 21751005 in words is "twenty-one million, seven hundred fifty-one thousand, five".