21453478 has 8 divisors (see below), whose sum is σ = 32200272. Its totient is φ = 10720056.

The previous prime is 21453469. The next prime is 21453493. The reversal of 21453478 is 87435412.

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

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, 3351 + ... + 7357.

It is an arithmetic number, because the mean of its divisors is an integer number (4025034).

Almost surely, 2^21453478 is an apocalyptic number.

21453478 is a deficient number, since it is larger than the sum of its proper divisors (10746794).

21453478 is a wasteful number, since it uses less digits than its factorization.

21453478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6686.

The product of its digits is 26880, while the sum is 34.

The square root of 21453478 is about 4631.7899347876. The cubic root of 21453478 is about 277.8641832651.

The spelling of 21453478 in words is "twenty-one million, four hundred fifty-three thousand, four hundred seventy-eight".