20658720 has 96 divisors (see below), whose sum is σ = 65705472. Its totient is φ = 5455872.

The previous prime is 20658707. The next prime is 20658721. The reversal of 20658720 is 2785602.

It is a tau number, because it is divible by the number of its divisors (96).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (20658721) 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 15 ways as a sum of consecutive naturals, for example, 92529 + ... + 92751.

It is an arithmetic number, because the mean of its divisors is an integer number (684432).

Almost surely, 2^20658720 is an apocalyptic number.

20658720 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 20658720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32852736).

20658720 is an abundant number, since it is smaller than the sum of its proper divisors (45046752).

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

20658720 is a wasteful number, since it uses less digits than its factorization.

20658720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 434 (or 426 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 20658720 is about 4545.1864648219. The cubic root of 20658720 is about 274.3896989166.

The spelling of 20658720 in words is "twenty million, six hundred fifty-eight thousand, seven hundred twenty".