20663655440 has 20 divisors (see below), whose sum is σ = 48042999084. Its totient is φ = 8265462144.

The previous prime is 20663655433. The next prime is 20663655451. The reversal of 20663655440 is 4455636602.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 7280867584 + 13382787856 = 85328^2 + 115684^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×20663655440² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129147767 + ... + 129147926.

Almost surely, 2^20663655440 is an apocalyptic number.

20663655440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20663655440 is an abundant number, since it is smaller than the sum of its proper divisors (27379343644).

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

20663655440 is a wasteful number, since it uses less digits than its factorization.

20663655440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258295706 (or 258295700 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 41.

The spelling of 20663655440 in words is "twenty billion, six hundred sixty-three million, six hundred fifty-five thousand, four hundred forty".