20669540 has 24 divisors (see below), whose sum is σ = 43605240. Its totient is φ = 8229888.

The previous prime is 20669531. The next prime is 20669543. The reversal of 20669540 is 4596602.

It can be written as a sum of positive squares in 4 ways, for example, as 813604 + 19855936 = 902^2 + 4456^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20669497 and 20669506.

It is not an unprimeable number, because it can be changed into a prime (20669543) 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, 2324 + ... + 6836.

It is an arithmetic number, because the mean of its divisors is an integer number (1816885).

Almost surely, 2^20669540 is an apocalyptic number.

20669540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20669540 is an abundant number, since it is smaller than the sum of its proper divisors (22935700).

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

20669540 is a wasteful number, since it uses less digits than its factorization.

20669540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4751 (or 4749 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 20669540 is about 4546.3765792112. The cubic root of 20669540 is about 274.4375944037.

The spelling of 20669540 in words is "twenty million, six hundred sixty-nine thousand, five hundred forty".