21064945 has 8 divisors (see below), whose sum is σ = 27576000. Its totient is φ = 15319920.

The previous prime is 21064943. The next prime is 21064957. The reversal of 21064945 is 54946012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21064945 - 2¹ = 21064943 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21064943) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 191445 + ... + 191554.

It is an arithmetic number, because the mean of its divisors is an integer number (3447000).

Almost surely, 2^21064945 is an apocalyptic number.

It is an amenable number.

21064945 is a deficient number, since it is larger than the sum of its proper divisors (6511055).

21064945 is a wasteful number, since it uses less digits than its factorization.

21064945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383015.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 21064945 is about 4589.6563052150. The cubic root of 21064945 is about 276.1765349988.

The spelling of 21064945 in words is "twenty-one million, sixty-four thousand, nine hundred forty-five".