21065064 has 32 divisors (see below), whose sum is σ = 52902720. Its totient is φ = 6989696.

The previous prime is 21065063. The next prime is 21065081. The reversal of 21065064 is 46056012.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (21065063) 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 7 ways as a sum of consecutive naturals, for example, 3709 + ... + 7475.

It is an arithmetic number, because the mean of its divisors is an integer number (1653210).

Almost surely, 2^21065064 is an apocalyptic number.

21065064 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21065064 is an abundant number, since it is smaller than the sum of its proper divisors (31837656).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21065064 is a wasteful number, since it uses less digits than its factorization.

21065064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4009 (or 4005 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 21065064 is about 4589.6692691304. The cubic root of 21065064 is about 276.1770550563.

The spelling of 21065064 in words is "twenty-one million, sixty-five thousand, sixty-four".