20993280 has 288 divisors, whose sum is σ = 84768768. Its totient is φ = 4300800.

The previous prime is 20993279. The next prime is 20993281. The reversal of 20993280 is 8239902.

It is an interprime number because it is at equal distance from previous prime (20993279) and next prime (20993281).

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20993281) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 295645 + ... + 295715.

It is an arithmetic number, because the mean of its divisors is an integer number (294336).

Almost surely, 2^20993280 is an apocalyptic number.

20993280 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 20993280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42384384).

20993280 is an abundant number, since it is smaller than the sum of its proper divisors (63775488).

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

20993280 is a wasteful number, since it uses less digits than its factorization.

20993280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113 (or 99 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 20993280 is about 4581.8424241783. The cubic root of 20993280 is about 275.8629859740.

It can be divided in two parts, 209932 and 80, that added together give a palindrome (210012).

The spelling of 20993280 in words is "twenty million, nine hundred ninety-three thousand, two hundred eighty".