6721378 has 4 divisors (see below), whose sum is σ = 10082070. Its totient is φ = 3360688.

The previous prime is 6721367. The next prime is 6721381. The reversal of 6721378 is 8731276.

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

It can be written as a sum of positive squares in only one way, i.e., 5414929 + 1306449 = 2327^2 + 1143^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1680343 + ... + 1680346.

Almost surely, 2^6721378 is an apocalyptic number.

6721378 is a deficient number, since it is larger than the sum of its proper divisors (3360692).

6721378 is a wasteful number, since it uses less digits than its factorization.

6721378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3360691.

The product of its digits is 14112, while the sum is 34.

The square root of 6721378 is about 2592.5620532593. The cubic root of 6721378 is about 188.7206571055.

The spelling of 6721378 in words is "six million, seven hundred twenty-one thousand, three hundred seventy-eight".