21002378 has 8 divisors (see below), whose sum is σ = 33356772. Its totient is φ = 9883456.

The previous prime is 21002357. The next prime is 21002389. The reversal of 21002378 is 87320012.

It can be written as a sum of positive squares in 2 ways, for example, as 20367169 + 635209 = 4513^2 + 797^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 308825 + ... + 308892.

Almost surely, 2^21002378 is an apocalyptic number.

21002378 is a deficient number, since it is larger than the sum of its proper divisors (12354394).

21002378 is a wasteful number, since it uses less digits than its factorization.

21002378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 617736.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 21002378 is about 4582.8351486825. The cubic root of 21002378 is about 275.9028310890.

The spelling of 21002378 in words is "twenty-one million, two thousand, three hundred seventy-eight".