21775505 has 8 divisors (see below), whose sum is σ = 26236224. Its totient is φ = 17350000.

The previous prime is 21775493. The next prime is 21775531. The reversal of 21775505 is 50557712.

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

It is not a de Polignac number, because 21775505 - 2⁴ = 21775489 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7421 + ... + 9930.

It is an arithmetic number, because the mean of its divisors is an integer number (3279528).

Almost surely, 2^21775505 is an apocalyptic number.

It is an amenable number.

21775505 is a deficient number, since it is larger than the sum of its proper divisors (4460719).

21775505 is a wasteful number, since it uses less digits than its factorization.

21775505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17607.

The product of its (nonzero) digits is 12250, while the sum is 32.

The square root of 21775505 is about 4666.4231484082. The cubic root of 21775505 is about 279.2475759641.

The spelling of 21775505 in words is "twenty-one million, seven hundred seventy-five thousand, five hundred five".