20615449 has 4 divisors (see below), whose sum is σ = 20655540. Its totient is φ = 20575360.

The previous prime is 20615443. The next prime is 20615453. The reversal of 20615449 is 94451602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9272025 + 11343424 = 3045^2 + 3368^2 .

It is a cyclic number.

It is not a de Polignac number, because 20615449 - 2⁵ = 20615417 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20615449.

It is not an unprimeable number, because it can be changed into a prime (20615443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19264 + ... + 20305.

It is an arithmetic number, because the mean of its divisors is an integer number (5163885).

Almost surely, 2^20615449 is an apocalyptic number.

It is an amenable number.

20615449 is a deficient number, since it is larger than the sum of its proper divisors (40091).

20615449 is an equidigital number, since it uses as much as digits as its factorization.

20615449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40090.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 20615449 is about 4540.4238788906. The cubic root of 20615449 is about 274.1979894595.

The spelling of 20615449 in words is "twenty million, six hundred fifteen thousand, four hundred forty-nine".