21740400 has 300 divisors, whose sum is σ = 86513064. Its totient is φ = 5184000.

The previous prime is 21740387. The next prime is 21740417. The reversal of 21740400 is 404712.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (300).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 356370 + ... + 356430.

Almost surely, 2^21740400 is an apocalyptic number.

21740400 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 21740400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43256532).

21740400 is an abundant number, since it is smaller than the sum of its proper divisors (64772664).

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

21740400 is a wasteful number, since it uses less digits than its factorization.

21740400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 21740400 is about 4662.6601849159. The cubic root of 21740400 is about 279.0974338850.

The spelling of 21740400 in words is "twenty-one million, seven hundred forty thousand, four hundred".