20810400 has 288 divisors, whose sum is σ = 78744960. Its totient is φ = 4730880.

The previous prime is 20810399. The next prime is 20810407. The reversal of 20810400 is 401802.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 20810400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20810407) 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 47 ways as a sum of consecutive naturals, for example, 717586 + ... + 717614.

It is an arithmetic number, because the mean of its divisors is an integer number (273420).

Almost surely, 2^20810400 is an apocalyptic number.

20810400 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 20810400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39372480).

20810400 is an abundant number, since it is smaller than the sum of its proper divisors (57934560).

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

20810400 is a wasteful number, since it uses less digits than its factorization.

20810400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88 (or 75 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 20810400 is about 4561.8417333353. The cubic root of 20810400 is about 275.0596014066.

The spelling of 20810400 in words is "twenty million, eight hundred ten thousand, four hundred".