21330878 has 16 divisors (see below), whose sum is σ = 32503680. Its totient is φ = 10497816.

The previous prime is 21330853. The next prime is 21330887. The reversal of 21330878 is 87803312.

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56093 + ... + 56471.

It is an arithmetic number, because the mean of its divisors is an integer number (2031480).

Almost surely, 2^21330878 is an apocalyptic number.

21330878 is a deficient number, since it is larger than the sum of its proper divisors (11172802).

21330878 is a wasteful number, since it uses less digits than its factorization.

21330878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 751.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 21330878 is about 4618.5363482385. The cubic root of 21330878 is about 277.3338691255. Note that the first 3 decimals are identical.

The spelling of 21330878 in words is "twenty-one million, three hundred thirty thousand, eight hundred seventy-eight".