21063278 has 4 divisors (see below), whose sum is σ = 31594920. Its totient is φ = 10531638.

The previous prime is 21063257. The next prime is 21063281. The reversal of 21063278 is 87236012.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21063278.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5265818 + ... + 5265821.

It is an arithmetic number, because the mean of its divisors is an integer number (7898730).

Almost surely, 2^21063278 is an apocalyptic number.

21063278 is a deficient number, since it is larger than the sum of its proper divisors (10531642).

21063278 is a wasteful number, since it uses less digits than its factorization.

21063278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10531641.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 21063278 is about 4589.4746976097. The cubic root of 21063278 is about 276.1692496181.

The spelling of 21063278 in words is "twenty-one million, sixty-three thousand, two hundred seventy-eight".