20655240 has 32 divisors (see below), whose sum is σ = 61966080. Its totient is φ = 5508032.

The previous prime is 20655227. The next prime is 20655241. The reversal of 20655240 is 4255602.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20655240.

It is not an unprimeable number, because it can be changed into a prime (20655241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85944 + ... + 86183.

It is an arithmetic number, because the mean of its divisors is an integer number (1936440).

Almost surely, 2^20655240 is an apocalyptic number.

20655240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20655240 is an abundant number, since it is smaller than the sum of its proper divisors (41310840).

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

20655240 is a wasteful number, since it uses less digits than its factorization.

20655240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172141 (or 172137 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 20655240 is about 4544.8036261207. The cubic root of 20655240 is about 274.3742908988.

The spelling of 20655240 in words is "twenty million, six hundred fifty-five thousand, two hundred forty".