21715005 has 32 divisors (see below), whose sum is σ = 39392640. Its totient is φ = 10126080.

The previous prime is 21715003. The next prime is 21715007. The reversal of 21715005 is 50051712.

It is an interprime number because it is at equal distance from previous prime (21715003) and next prime (21715007).

It is not a de Polignac number, because 21715005 - 2¹ = 21715003 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21715003) 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 31 ways as a sum of consecutive naturals, for example, 775 + ... + 6635.

It is an arithmetic number, because the mean of its divisors is an integer number (1231020).

Almost surely, 2^21715005 is an apocalyptic number.

It is an amenable number.

21715005 is a deficient number, since it is larger than the sum of its proper divisors (17677635).

21715005 is a wasteful number, since it uses less digits than its factorization.

21715005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5901.

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

The square root of 21715005 is about 4659.9361583610. The cubic root of 21715005 is about 278.9887201411.

Adding to 21715005 its reverse (50051712), we get a palindrome (71766717).

The spelling of 21715005 in words is "twenty-one million, seven hundred fifteen thousand, five".