21378274 has 4 divisors (see below), whose sum is σ = 32067414. Its totient is φ = 10689136.

The previous prime is 21378271. The next prime is 21378277. The reversal of 21378274 is 47287312.

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

It is an interprime number because it is at equal distance from previous prime (21378271) and next prime (21378277).

It can be written as a sum of positive squares in only one way, i.e., 15093225 + 6285049 = 3885^2 + 2507^2 .

It is not an unprimeable number, because it can be changed into a prime (21378271) 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 as a sum of consecutive naturals, namely, 5344567 + ... + 5344570.

Almost surely, 2^21378274 is an apocalyptic number.

21378274 is a deficient number, since it is larger than the sum of its proper divisors (10689140).

21378274 is a wasteful number, since it uses less digits than its factorization.

21378274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10689139.

The product of its digits is 18816, while the sum is 34.

The square root of 21378274 is about 4623.6645639579. The cubic root of 21378274 is about 277.5391238835.

It can be divided in two parts, 213 and 78274, that added together give a palindrome (78487).

The spelling of 21378274 in words is "twenty-one million, three hundred seventy-eight thousand, two hundred seventy-four".