20491800 has 288 divisors, whose sum is σ = 80151120. Its totient is φ = 4300800.

The previous prime is 20491799. The next prime is 20491811. The reversal of 20491800 is 819402.

20491800 is nontrivially palindromic in base 13.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

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 71 ways as a sum of consecutive naturals, for example, 499780 + ... + 499820.

Almost surely, 2^20491800 is an apocalyptic number.

20491800 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 20491800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40075560).

20491800 is an abundant number, since it is smaller than the sum of its proper divisors (59659320).

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

20491800 is a wasteful number, since it uses less digits than its factorization.

20491800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91 (or 75 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 20491800 is about 4526.7869399829. The cubic root of 20491800 is about 273.6486875155.

The spelling of 20491800 in words is "twenty million, four hundred ninety-one thousand, eight hundred".