20640550 has 48 divisors (see below), whose sum is σ = 46470240. Its totient is φ = 6658560.

The previous prime is 20640541. The next prime is 20640553. The reversal of 20640550 is 5504602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20640553) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4216 + ... + 7684.

It is an arithmetic number, because the mean of its divisors is an integer number (968130).

Almost surely, 2^20640550 is an apocalyptic number.

20640550 is an abundant number, since it is smaller than the sum of its proper divisors (25829690).

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

20640550 is a wasteful number, since it uses less digits than its factorization.

20640550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3505 (or 3500 counting only the distinct ones).

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

The square root of 20640550 is about 4543.1872072368. The cubic root of 20640550 is about 274.3092305038.

The spelling of 20640550 in words is "twenty million, six hundred forty thousand, five hundred fifty".