21400470 has 192 divisors, whose sum is σ = 71677440. Its totient is φ = 4447872.

The previous prime is 21400459. The next prime is 21400487. The reversal of 21400470 is 7400412.

It is a happy number.

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 95 ways as a sum of consecutive naturals, for example, 319377 + ... + 319443.

It is an arithmetic number, because the mean of its divisors is an integer number (373320).

Almost surely, 2^21400470 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21400470, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35838720).

21400470 is an abundant number, since it is smaller than the sum of its proper divisors (50276970).

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

21400470 is a wasteful number, since it uses less digits than its factorization.

21400470 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116 (or 97 counting only the distinct ones).

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

The square root of 21400470 is about 4626.0642018891. The cubic root of 21400470 is about 277.6351423562.

Adding to 21400470 its reverse (7400412), we get a palindrome (28800882).

The spelling of 21400470 in words is "twenty-one million, four hundred thousand, four hundred seventy".