20509741 has 4 divisors (see below), whose sum is σ = 23439712. Its totient is φ = 17579772.

The previous prime is 20509739. The next prime is 20509747. The reversal of 20509741 is 14790502.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20509741 - 2¹ = 20509739 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20509747) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1464975 + ... + 1464988.

It is an arithmetic number, because the mean of its divisors is an integer number (5859928).

Almost surely, 2^20509741 is an apocalyptic number.

It is an amenable number.

20509741 is a deficient number, since it is larger than the sum of its proper divisors (2929971).

20509741 is an equidigital number, since it uses as much as digits as its factorization.

20509741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2929970.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 20509741 is about 4528.7681548077. The cubic root of 20509741 is about 273.7285259387.

The spelling of 20509741 in words is "twenty million, five hundred nine thousand, seven hundred forty-one".