21278414 has 4 divisors (see below), whose sum is σ = 31917624. Its totient is φ = 10639206.

The previous prime is 21278401. The next prime is 21278417. The reversal of 21278414 is 41487212.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21278417) 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, 5319602 + ... + 5319605.

It is an arithmetic number, because the mean of its divisors is an integer number (7979406).

Almost surely, 2^21278414 is an apocalyptic number.

21278414 is a deficient number, since it is larger than the sum of its proper divisors (10639210).

21278414 is a wasteful number, since it uses less digits than its factorization.

21278414 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10639209.

The product of its digits is 3584, while the sum is 29.

The square root of 21278414 is about 4612.8531301137. The cubic root of 21278414 is about 277.1063118537.

The spelling of 21278414 in words is "twenty-one million, two hundred seventy-eight thousand, four hundred fourteen".