20724835 has 4 divisors (see below), whose sum is σ = 24869808. Its totient is φ = 16579864.

The previous prime is 20724827. The next prime is 20724841. The reversal of 20724835 is 53842702.

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

It is a cyclic number.

It is not a de Polignac number, because 20724835 - 2³ = 20724827 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20724797 and 20724806.

It is an unprimeable number.

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, 2072479 + ... + 2072488.

It is an arithmetic number, because the mean of its divisors is an integer number (6217452).

Almost surely, 2^20724835 is an apocalyptic number.

20724835 is a deficient number, since it is larger than the sum of its proper divisors (4144973).

20724835 is an equidigital number, since it uses as much as digits as its factorization.

20724835 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4144972.

The product of its (nonzero) digits is 13440, while the sum is 31.

The square root of 20724835 is about 4552.4537339769. The cubic root of 20724835 is about 274.6821009710.

The spelling of 20724835 in words is "twenty million, seven hundred twenty-four thousand, eight hundred thirty-five".