20663954640 has 720 divisors, whose sum is σ = 87988118400. Its totient is φ = 4316239872.

The previous prime is 20663954627. The next prime is 20663954671. The reversal of 20663954640 is 4645936602.

20663954640 = T₃₇₇₃₆ + T₃₇₇₃₇ + ... + T₃₇₇₆₄.

20663954640 is a `hidden beast` number, since 2 + 0 + 6 + 63 + 9 + 546 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 19438749 + ... + 19439811.

It is an arithmetic number, because the mean of its divisors is an integer number (122205720).

Almost surely, 2^20663954640 is an apocalyptic number.

20663954640 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 20663954640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43994059200).

20663954640 is an abundant number, since it is smaller than the sum of its proper divisors (67324163760).

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

20663954640 is a wasteful number, since it uses less digits than its factorization.

20663954640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1144 (or 1128 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 45.

The spelling of 20663954640 in words is "twenty billion, six hundred sixty-three million, nine hundred fifty-four thousand, six hundred forty".