20963840 has 80 divisors (see below), whose sum is σ = 53032320. Its totient is φ = 7925760.

The previous prime is 20963837. The next prime is 20963849. The reversal of 20963840 is 4836902.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 20963797 and 20963806.

It is not an unprimeable number, because it can be changed into a prime (20963849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48425 + ... + 48855.

It is an arithmetic number, because the mean of its divisors is an integer number (662904).

Almost surely, 2^20963840 is an apocalyptic number.

20963840 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 20963840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26516160).

20963840 is an abundant number, since it is smaller than the sum of its proper divisors (32068480).

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

20963840 is an equidigital number, since it uses as much as digits as its factorization.

20963840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473 (or 457 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 20963840 is about 4578.6286156446. The cubic root of 20963840 is about 275.7339731720.

The spelling of 20963840 in words is "twenty million, nine hundred sixty-three thousand, eight hundred forty".