21068778 has 32 divisors (see below), whose sum is σ = 43776000. Its totient is φ = 6752880.

The previous prime is 21068741. The next prime is 21068807. The reversal of 21068778 is 87786012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41973 + ... + 42471.

It is an arithmetic number, because the mean of its divisors is an integer number (1368000).

Almost surely, 2^21068778 is an apocalyptic number.

21068778 is an abundant number, since it is smaller than the sum of its proper divisors (22707222).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21068778 is a wasteful number, since it uses less digits than its factorization.

21068778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 762.

The product of its (nonzero) digits is 37632, while the sum is 39.

The square root of 21068778 is about 4590.0738556150. The cubic root of 21068778 is about 276.1932851091.

The spelling of 21068778 in words is "twenty-one million, sixty-eight thousand, seven hundred seventy-eight".