21123064 has 8 divisors (see below), whose sum is σ = 39605760. Its totient is φ = 10561528.

The previous prime is 21123043. The next prime is 21123073. The reversal of 21123064 is 46032112.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 1320184 + ... + 1320199.

It is an arithmetic number, because the mean of its divisors is an integer number (4950720).

Almost surely, 2^21123064 is an apocalyptic number.

It is an amenable number.

21123064 is a deficient number, since it is larger than the sum of its proper divisors (18482696).

21123064 is a wasteful number, since it uses less digits than its factorization.

21123064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2640389 (or 2640385 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21123064 is about 4595.9834638519. The cubic root of 21123064 is about 276.4302956859.

Adding to 21123064 its reverse (46032112), we get a palindrome (67155176).

The spelling of 21123064 in words is "twenty-one million, one hundred twenty-three thousand, sixty-four".