21155826 has 32 divisors (see below), whose sum is σ = 44126208. Its totient is φ = 6754320.

The previous prime is 21155789. The next prime is 21155839. The reversal of 21155826 is 62855112.

It is a junction number, because it is equal to n+sod(n) for n = 21155793 and 21155802.

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, 19371 + ... + 20433.

It is an arithmetic number, because the mean of its divisors is an integer number (1378944).

Almost surely, 2^21155826 is an apocalyptic number.

21155826 is an abundant number, since it is smaller than the sum of its proper divisors (22970382).

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

21155826 is a wasteful number, since it uses less digits than its factorization.

21155826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1206.

The product of its digits is 4800, while the sum is 30.

The square root of 21155826 is about 4599.5462819717. The cubic root of 21155826 is about 276.5731368822.

The spelling of 21155826 in words is "twenty-one million, one hundred fifty-five thousand, eight hundred twenty-six".