20506240 has 48 divisors (see below), whose sum is σ = 49298130. Its totient is φ = 8156672.

The previous prime is 20506201. The next prime is 20506243. The reversal of 20506240 is 4260502.

It can be written as a sum of positive squares in only one way, i.e., 18455616 + 2050624 = 4296^2 + 1432^2 .

It is not an unprimeable number, because it can be changed into a prime (20506243) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 114471 + ... + 114649.

Almost surely, 2^20506240 is an apocalyptic number.

20506240 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 20506240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24649065).

20506240 is an abundant number, since it is smaller than the sum of its proper divisors (28791890).

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

20506240 is an frugal number, since it uses more digits than its factorization.

20506240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 377 (or 186 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 20506240 is about 4528.3816093611. The cubic root of 20506240 is about 273.7129499561.

Adding to 20506240 its reverse (4260502), we get a palindrome (24766742).

The spelling of 20506240 in words is "twenty million, five hundred six thousand, two hundred forty".