21034855 has 4 divisors (see below), whose sum is σ = 25241832. Its totient is φ = 16827880.

The previous prime is 21034847. The next prime is 21034859. The reversal of 21034855 is 55843012.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21034855 - 2³ = 21034847 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21034859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2103481 + ... + 2103490.

It is an arithmetic number, because the mean of its divisors is an integer number (6310458).

Almost surely, 2^21034855 is an apocalyptic number.

21034855 is a deficient number, since it is larger than the sum of its proper divisors (4206977).

21034855 is an equidigital number, since it uses as much as digits as its factorization.

21034855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4206976.

The product of its (nonzero) digits is 4800, while the sum is 28.

The square root of 21034855 is about 4586.3771105307. The cubic root of 21034855 is about 276.0449718429.

Adding to 21034855 its reverse (55843012), we get a palindrome (76877867).

The spelling of 21034855 in words is "twenty-one million, thirty-four thousand, eight hundred fifty-five".