20644530 has 32 divisors (see below), whose sum is σ = 49918464. Its totient is φ = 5463936.

The previous prime is 20644489. The next prime is 20644537. The reversal of 20644530 is 3544602.

It is a self number, because there is not a number n which added to its sum of digits gives 20644530.

It is not an unprimeable number, because it can be changed into a prime (20644537) 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 15 ways as a sum of consecutive naturals, for example, 1599 + ... + 6621.

It is an arithmetic number, because the mean of its divisors is an integer number (1559952).

Almost surely, 2^20644530 is an apocalyptic number.

20644530 is an abundant number, since it is smaller than the sum of its proper divisors (29273934).

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

20644530 is a wasteful number, since it uses less digits than its factorization.

20644530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5170.

The product of its (nonzero) digits is 2880, while the sum is 24.

The square root of 20644530 is about 4543.6252046136. The cubic root of 20644530 is about 274.3268605342.

The spelling of 20644530 in words is "twenty million, six hundred forty-four thousand, five hundred thirty".