20657735280 has 720 divisors, whose sum is σ = 87224417280. Its totient is φ = 4289366016.

The previous prime is 20657735239. The next prime is 20657735297. The reversal of 20657735280 is 8253775602.

20657735280 is a `hidden beast` number, since 2 + 0 + 6 + 57 + 73 + 528 + 0 = 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 polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 67288887 + ... + 67289193.

It is an arithmetic number, because the mean of its divisors is an integer number (121145024).

Almost surely, 2^20657735280 is an apocalyptic number.

20657735280 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 20657735280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43612208640).

20657735280 is an abundant number, since it is smaller than the sum of its proper divisors (66566682000).

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

20657735280 is a wasteful number, since it uses less digits than its factorization.

20657735280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 438 (or 416 counting only the distinct ones).

The product of its (nonzero) digits is 705600, while the sum is 45.

The spelling of 20657735280 in words is "twenty billion, six hundred fifty-seven million, seven hundred thirty-five thousand, two hundred eighty".