21975505 has 8 divisors (see below), whose sum is σ = 26509824. Its totient is φ = 17487600.

The previous prime is 21975487. The next prime is 21975517. The reversal of 21975505 is 50557912.

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

It is not a de Polignac number, because 21975505 - 2⁷ = 21975377 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, 10551 + ... + 12460.

It is an arithmetic number, because the mean of its divisors is an integer number (3313728).

Almost surely, 2^21975505 is an apocalyptic number.

It is an amenable number.

21975505 is a deficient number, since it is larger than the sum of its proper divisors (4534319).

21975505 is a wasteful number, since it uses less digits than its factorization.

21975505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23207.

The product of its (nonzero) digits is 15750, while the sum is 34.

The square root of 21975505 is about 4687.8038568182. The cubic root of 21975505 is about 280.0999005769.

The spelling of 21975505 in words is "twenty-one million, nine hundred seventy-five thousand, five hundred five".