21481400 has 48 divisors (see below), whose sum is σ = 52582200. Its totient is φ = 8138880.

The previous prime is 21481399. The next prime is 21481403. The reversal of 21481400 is 418412.

It is a super-2 number, since 2×21481400² = 922901091920000, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21481403) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 974 + ... + 6626.

Almost surely, 2^21481400 is an apocalyptic number.

21481400 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 21481400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26291100).

21481400 is an abundant number, since it is smaller than the sum of its proper divisors (31100800).

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

21481400 is a wasteful number, since it uses less digits than its factorization.

21481400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5688 (or 5679 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 21481400 is about 4634.8031241899. The cubic root of 21481400 is about 277.9846790376.

Adding to 21481400 its reverse (418412), we get a palindrome (21899812).

The spelling of 21481400 in words is "twenty-one million, four hundred eighty-one thousand, four hundred".