21011078 has 16 divisors (see below), whose sum is σ = 34461504. Its totient is φ = 9528360.

The previous prime is 21011071. The next prime is 21011083. The reversal of 21011078 is 87011012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011071) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12101 + ... + 13727.

It is an arithmetic number, because the mean of its divisors is an integer number (2153844).

Almost surely, 2^21011078 is an apocalyptic number.

21011078 is a deficient number, since it is larger than the sum of its proper divisors (13450426).

21011078 is a wasteful number, since it uses less digits than its factorization.

21011078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2227.

The product of its (nonzero) digits is 112, while the sum is 20.

The square root of 21011078 is about 4583.7842444862. The cubic root of 21011078 is about 275.9409223830.

The spelling of 21011078 in words is "twenty-one million, eleven thousand, seventy-eight".