21715066 has 16 divisors (see below), whose sum is σ = 34103808. Its totient is φ = 10357200.

The previous prime is 21715063. The next prime is 21715087. The reversal of 21715066 is 66051712.

It is not an unprimeable number, because it can be changed into a prime (21715061) 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 7 ways as a sum of consecutive naturals, for example, 1936 + ... + 6868.

It is an arithmetic number, because the mean of its divisors is an integer number (2131488).

Almost surely, 2^21715066 is an apocalyptic number.

21715066 is a deficient number, since it is larger than the sum of its proper divisors (12388742).

21715066 is a wasteful number, since it uses less digits than its factorization.

21715066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5037.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 21715066 is about 4659.9427035104. The cubic root of 21715066 is about 278.9889813782.

Adding to 21715066 its reverse (66051712), we get a palindrome (87766778).

The spelling of 21715066 in words is "twenty-one million, seven hundred fifteen thousand, sixty-six".