21375505 has 8 divisors (see below), whose sum is σ = 25696512. Its totient is φ = 17069808.

The previous prime is 21375503. The next prime is 21375517. The reversal of 21375505 is 50557312.

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

It is a cyclic number.

It is not a de Polignac number, because 21375505 - 2¹ = 21375503 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21375503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 487 + ... + 6556.

It is an arithmetic number, because the mean of its divisors is an integer number (3212064).

Almost surely, 2^21375505 is an apocalyptic number.

It is an amenable number.

21375505 is a deficient number, since it is larger than the sum of its proper divisors (4321007).

21375505 is an equidigital number, since it uses as much as digits as its factorization.

21375505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7655.

The product of its (nonzero) digits is 5250, while the sum is 28.

The square root of 21375505 is about 4623.3651164493. The cubic root of 21375505 is about 277.5271407050.

The spelling of 21375505 in words is "twenty-one million, three hundred seventy-five thousand, five hundred five".