21403398 has 8 divisors (see below), whose sum is σ = 42806808. Its totient is φ = 7134464.

The previous prime is 21403337. The next prime is 21403399. The reversal of 21403398 is 89330412.

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

21403398 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21403399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1783611 + ... + 1783622.

It is an arithmetic number, because the mean of its divisors is an integer number (5350851).

Almost surely, 2^21403398 is an apocalyptic number.

21403398 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21403398 is a wasteful number, since it uses less digits than its factorization.

21403398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3567238.

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 21403398 is about 4626.3806587872. The cubic root of 21403398 is about 277.6478037390.

The spelling of 21403398 in words is "twenty-one million, four hundred three thousand, three hundred ninety-eight".