20655440 has 40 divisors (see below), whose sum is σ = 51720648. Its totient is φ = 7626240.

The previous prime is 20655433. The next prime is 20655457. The reversal of 20655440 is 4455602.

It can be written as a sum of positive squares in 4 ways, for example, as 906304 + 19749136 = 952^2 + 4444^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8891 + ... + 10970.

Almost surely, 2^20655440 is an apocalyptic number.

20655440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20655440 is an abundant number, since it is smaller than the sum of its proper divisors (31065208).

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

20655440 is a wasteful number, since it uses less digits than its factorization.

20655440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19887 (or 19881 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 26.

The square root of 20655440 is about 4544.8256292184. The cubic root of 20655440 is about 274.3751764640.

The spelling of 20655440 in words is "twenty million, six hundred fifty-five thousand, four hundred forty".