21319478 has 4 divisors (see below), whose sum is σ = 31979220. Its totient is φ = 10659738.

The previous prime is 21319477. The next prime is 21319481. The reversal of 21319478 is 87491312.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21319471) by changing a digit.

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 as a sum of consecutive naturals, namely, 5329868 + ... + 5329871.

It is an arithmetic number, because the mean of its divisors is an integer number (7994805).

Almost surely, 2^21319478 is an apocalyptic number.

21319478 is a deficient number, since it is larger than the sum of its proper divisors (10659742).

21319478 is a wasteful number, since it uses less digits than its factorization.

21319478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10659741.

The product of its digits is 12096, while the sum is 35.

The square root of 21319478 is about 4617.3020260754. The cubic root of 21319478 is about 277.2844545397.

It can be divided in two parts, 213 and 19478, that added together give a palindrome (19691).

The spelling of 21319478 in words is "twenty-one million, three hundred nineteen thousand, four hundred seventy-eight".