21706064 has 10 divisors (see below), whose sum is σ = 42055530. Its totient is φ = 10853024.

The previous prime is 21706033. The next prime is 21706067. The reversal of 21706064 is 46060712.

It can be written as a sum of positive squares in only one way, i.e., 13249600 + 8456464 = 3640^2 + 2908^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21706067) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 678299 + ... + 678330.

It is an arithmetic number, because the mean of its divisors is an integer number (4205553).

Almost surely, 2^21706064 is an apocalyptic number.

It is an amenable number.

21706064 is a deficient number, since it is larger than the sum of its proper divisors (20349466).

21706064 is a wasteful number, since it uses less digits than its factorization.

21706064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1356637 (or 1356631 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 21706064 is about 4658.9767116825. The cubic root of 21706064 is about 278.9504243393.

Adding to 21706064 its reverse (46060712), we get a palindrome (67766776).

The spelling of 21706064 in words is "twenty-one million, seven hundred six thousand, sixty-four".