20913500 has 48 divisors (see below), whose sum is σ = 46143552. Its totient is φ = 8280000.

The previous prime is 20913493. The next prime is 20913511. The reversal of 20913500 is 531902.

20913500 = T₄₄₉ + T₄₅₀ + ... + T₅₉₉.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75362 + ... + 75638.

It is an arithmetic number, because the mean of its divisors is an integer number (961324).

Almost surely, 2^20913500 is an apocalyptic number.

20913500 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 20913500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23071776).

20913500 is an abundant number, since it is smaller than the sum of its proper divisors (25230052).

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

20913500 is a wasteful number, since it uses less digits than its factorization.

20913500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 447 (or 435 counting only the distinct ones).

The product of its (nonzero) digits is 270, while the sum is 20.

The square root of 20913500 is about 4573.1280323210. The cubic root of 20913500 is about 275.5130916712.

It can be divided in two parts, 209 and 13500, that multiplied together give a triangular number (2821500 = T₂₃₇₅).

The spelling of 20913500 in words is "twenty million, nine hundred thirteen thousand, five hundred".