20705520 has 240 divisors, whose sum is σ = 75995136. Its totient is φ = 4646400.

The previous prime is 20705513. The next prime is 20705537. The reversal of 20705520 is 2550702.

It is a tau number, because it is divible by the number of its divisors (240).

It is a hoax number, since the sum of its digits (21) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 667905 + ... + 667935.

Almost surely, 2^20705520 is an apocalyptic number.

20705520 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 20705520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37997568).

20705520 is an abundant number, since it is smaller than the sum of its proper divisors (55289616).

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

20705520 is a wasteful number, since it uses less digits than its factorization.

20705520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92 (or 75 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 21.

The square root of 20705520 is about 4550.3318560298. The cubic root of 20705520 is about 274.5967422886.

The spelling of 20705520 in words is "twenty million, seven hundred five thousand, five hundred twenty".