20645500 has 48 divisors (see below), whose sum is σ = 45549504. Its totient is φ = 8174400.

The previous prime is 20645483. The next prime is 20645539. The reversal of 20645500 is 554602.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78369 + ... + 78631.

It is an arithmetic number, because the mean of its divisors is an integer number (948948).

Almost surely, 2^20645500 is an apocalyptic number.

20645500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20645500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22774752).

20645500 is an abundant number, since it is smaller than the sum of its proper divisors (24904004).

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

20645500 is a wasteful number, since it uses less digits than its factorization.

20645500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439 (or 427 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 20645500 is about 4543.7319463190. The cubic root of 20645500 is about 274.3311569570.

The spelling of 20645500 in words is "twenty million, six hundred forty-five thousand, five hundred".