21775955 has 16 divisors (see below), whose sum is σ = 27388800. Its totient is φ = 16598400.

The previous prime is 21775937. The next prime is 21775969. The reversal of 21775955 is 55957712.

It is not a de Polignac number, because 21775955 - 2¹² = 21771859 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10505 + ... + 12405.

It is an arithmetic number, because the mean of its divisors is an integer number (1711800).

Almost surely, 2^21775955 is an apocalyptic number.

21775955 is a deficient number, since it is larger than the sum of its proper divisors (5612845).

21775955 is a wasteful number, since it uses less digits than its factorization.

21775955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2014.

The product of its digits is 110250, while the sum is 41.

The square root of 21775955 is about 4666.4713649609. The cubic root of 21775955 is about 279.2494995405.

The spelling of 21775955 in words is "twenty-one million, seven hundred seventy-five thousand, nine hundred fifty-five".