20505723 has 32 divisors (see below), whose sum is σ = 33592320. Its totient is φ = 10859520.

The previous prime is 20505713. The next prime is 20505761. The reversal of 20505723 is 32750502.

It is not a de Polignac number, because 20505723 - 2⁴ = 20505707 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20505693 and 20505702.

It is not an unprimeable number, because it can be changed into a prime (20505713) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24943 + ... + 25751.

It is an arithmetic number, because the mean of its divisors is an integer number (1049760).

Almost surely, 2^20505723 is an apocalyptic number.

20505723 is a deficient number, since it is larger than the sum of its proper divisors (13086597).

20505723 is a wasteful number, since it uses less digits than its factorization.

20505723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 907.

The product of its (nonzero) digits is 2100, while the sum is 24.

The square root of 20505723 is about 4528.3245245896. The cubic root of 20505723 is about 273.7106496680.

The spelling of 20505723 in words is "twenty million, five hundred five thousand, seven hundred twenty-three".