20953505 has 4 divisors (see below), whose sum is σ = 25144212. Its totient is φ = 16762800.

The previous prime is 20953481. The next prime is 20953531. The reversal of 20953505 is 50535902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50535902 = 2 ⋅25267951.

It can be written as a sum of positive squares in 2 ways, for example, as 11262736 + 9690769 = 3356^2 + 3113^2 .

It is a de Polignac number, because none of the positive numbers 2^k-20953505 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2095346 + ... + 2095355.

It is an arithmetic number, because the mean of its divisors is an integer number (6286053).

Almost surely, 2^20953505 is an apocalyptic number.

It is an amenable number.

20953505 is a deficient number, since it is larger than the sum of its proper divisors (4190707).

20953505 is an equidigital number, since it uses as much as digits as its factorization.

20953505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4190706.

The product of its (nonzero) digits is 6750, while the sum is 29.

The square root of 20953505 is about 4577.4998634626. The cubic root of 20953505 is about 275.6886541999.

The spelling of 20953505 in words is "twenty million, nine hundred fifty-three thousand, five hundred five".