20998400 has 108 divisors (see below), whose sum is σ = 55316772. Its totient is φ = 7864320.

The previous prime is 20998399. The next prime is 20998433. The reversal of 20998400 is 489902.

20998400 is an esthetic number in base 9, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 6 ways, for example, as 350464 + 20647936 = 592^2 + 4544^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 108704 + ... + 108896.

Almost surely, 2^20998400 is an apocalyptic number.

20998400 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 20998400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27658386).

20998400 is an abundant number, since it is smaller than the sum of its proper divisors (34318372).

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

20998400 is a wasteful number, since it uses less digits than its factorization.

20998400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236 (or 217 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 20998400 is about 4582.4011173183. The cubic root of 20998400 is about 275.8854106686.

The spelling of 20998400 in words is "twenty million, nine hundred ninety-eight thousand, four hundred".