21403478 has 8 divisors (see below), whose sum is σ = 33501168. Its totient is φ = 10236424.

The previous prime is 21403463. The next prime is 21403483. The reversal of 21403478 is 87430412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21403478.

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 3 ways as a sum of consecutive naturals, for example, 232601 + ... + 232692.

It is an arithmetic number, because the mean of its divisors is an integer number (4187646).

Almost surely, 2^21403478 is an apocalyptic number.

21403478 is a deficient number, since it is larger than the sum of its proper divisors (12097690).

21403478 is a wasteful number, since it uses less digits than its factorization.

21403478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 465318.

The product of its (nonzero) digits is 5376, while the sum is 29.

The square root of 21403478 is about 4626.3893048467. The cubic root of 21403478 is about 277.6481496622.

The spelling of 21403478 in words is "twenty-one million, four hundred three thousand, four hundred seventy-eight".