21769955 has 8 divisors (see below), whose sum is σ = 26165904. Its totient is φ = 17388000.

The previous prime is 21769939. The next prime is 21769961. The reversal of 21769955 is 55996712.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21769955 - 2⁴ = 21769939 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 305 + ... + 6605.

It is an arithmetic number, because the mean of its divisors is an integer number (3270738).

Almost surely, 2^21769955 is an apocalyptic number.

21769955 is a deficient number, since it is larger than the sum of its proper divisors (4395949).

21769955 is an equidigital number, since it uses as much as digits as its factorization.

21769955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6997.

The product of its digits is 170100, while the sum is 44.

The square root of 21769955 is about 4665.8284366230. The cubic root of 21769955 is about 279.2238496757.

The spelling of 21769955 in words is "twenty-one million, seven hundred sixty-nine thousand, nine hundred fifty-five".