21058856 has 32 divisors (see below), whose sum is σ = 48599040. Its totient is φ = 8330688.

The previous prime is 21058853. The next prime is 21058907. The reversal of 21058856 is 65885012.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21058853) 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, 13736 + ... + 15191.

It is an arithmetic number, because the mean of its divisors is an integer number (1518720).

Almost surely, 2^21058856 is an apocalyptic number.

21058856 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21058856 is an abundant number, since it is smaller than the sum of its proper divisors (27540184).

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

21058856 is a wasteful number, since it uses less digits than its factorization.

21058856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28953 (or 28949 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 35.

The square root of 21058856 is about 4588.9929178416. The cubic root of 21058856 is about 276.1499220489.

The spelling of 21058856 in words is "twenty-one million, fifty-eight thousand, eight hundred fifty-six".