21457064 has 16 divisors (see below), whose sum is σ = 40326900. Its totient is φ = 10703232.

The previous prime is 21457057. The next prime is 21457067. The reversal of 21457064 is 46075412.

It can be written as a sum of positive squares in 2 ways, for example, as 21436900 + 20164 = 4630^2 + 142^2 .

It is not an unprimeable number, because it can be changed into a prime (21457067) 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 in 3 ways as a sum of consecutive naturals, for example, 722 + ... + 6590.

Almost surely, 2^21457064 is an apocalyptic number.

It is an amenable number.

21457064 is a deficient number, since it is larger than the sum of its proper divisors (18869836).

21457064 is a wasteful number, since it uses less digits than its factorization.

21457064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6332 (or 6328 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 29.

The square root of 21457064 is about 4632.1770259782. The cubic root of 21457064 is about 277.8796642895.

The spelling of 21457064 in words is "twenty-one million, four hundred fifty-seven thousand, sixty-four".