20897736560400 has 720 divisors, whose sum is σ = 86792166999360. Its totient is φ = 4259030630400.

The previous prime is 20897736560357. The next prime is 20897736560401. The reversal of 20897736560400 is 406563779802.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is not an unprimeable number, because it can be changed into a prime (20897736560401) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 18442240 + ... + 19542560.

It is an arithmetic number, because the mean of its divisors is an integer number (120544676388).

Almost surely, 2^{20897736560400} is an apocalyptic number.

20897736560400 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 20897736560400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43396083499680).

20897736560400 is an abundant number, since it is smaller than the sum of its proper divisors (65894430438960).

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

20897736560400 is a wasteful number, since it uses less digits than its factorization.

20897736560400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1100392 (or 1100374 counting only the distinct ones).

The product of its (nonzero) digits is 15240960, while the sum is 57.

The spelling of 20897736560400 in words is "twenty trillion, eight hundred ninety-seven billion, seven hundred thirty-six million, five hundred sixty thousand, four hundred".