21064545 has 24 divisors (see below), whose sum is σ = 36743616. Its totient is φ = 11163168.

The previous prime is 21064523. The next prime is 21064553. The reversal of 21064545 is 54546012.

21064545 is a `hidden beast` number, since 2 + 10 + 645 + 4 + 5 = 666.

It is not a de Polignac number, because 21064545 - 2¹⁰ = 21063521 is a prime.

It is a Curzon number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 6114 + ... + 8916.

It is an arithmetic number, because the mean of its divisors is an integer number (1530984).

Almost surely, 2^21064545 is an apocalyptic number.

It is an amenable number.

21064545 is a deficient number, since it is larger than the sum of its proper divisors (15679071).

21064545 is a wasteful number, since it uses less digits than its factorization.

21064545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2981 (or 2978 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 21064545 is about 4589.6127287605. The cubic root of 21064545 is about 276.1747868921.

It can be divided in two parts, 21064 and 545, that added together give a square (21609 = 147²).

The spelling of 21064545 in words is "twenty-one million, sixty-four thousand, five hundred forty-five".