20569440 has 48 divisors (see below), whose sum is σ = 64795248. Its totient is φ = 5485056.

The previous prime is 20569433. The next prime is 20569441. The reversal of 20569440 is 4496502.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20569398 and 20569407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20569441) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 20947 + ... + 21906.

It is an arithmetic number, because the mean of its divisors is an integer number (1349901).

Almost surely, 2^20569440 is an apocalyptic number.

20569440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20569440 is an abundant number, since it is smaller than the sum of its proper divisors (44225808).

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

20569440 is a wasteful number, since it uses less digits than its factorization.

20569440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42871 (or 42863 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 20569440 is about 4535.3544514183. The cubic root of 20569440 is about 273.9938549779.

The spelling of 20569440 in words is "twenty million, five hundred sixty-nine thousand, four hundred forty".