21403470 has 64 divisors (see below), whose sum is σ = 56816640. Its totient is φ = 5116800.

The previous prime is 21403463. The next prime is 21403483. The reversal of 21403470 is 7430412.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 25660 + ... + 26480.

It is an arithmetic number, because the mean of its divisors is an integer number (887760).

Almost surely, 2^21403470 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21403470, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28408320).

21403470 is an abundant number, since it is smaller than the sum of its proper divisors (35413170).

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

21403470 is a wasteful number, since it uses less digits than its factorization.

21403470 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 921.

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 21403470 is about 4626.3884402415. The cubic root of 21403470 is about 277.6481150699.

Adding to 21403470 its reverse (7430412), we get a palindrome (28833882).

The spelling of 21403470 in words is "twenty-one million, four hundred three thousand, four hundred seventy".