20724985 has 8 divisors (see below), whose sum is σ = 25149960. Its totient is φ = 16393344.

The previous prime is 20724973. The next prime is 20725007. The reversal of 20724985 is 58942702.

It can be written as a sum of positive squares in 4 ways, for example, as 824464 + 19900521 = 908^2 + 4461^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20724985 - 2¹¹ = 20722937 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22842 + ... + 23731.

It is an arithmetic number, because the mean of its divisors is an integer number (3143745).

Almost surely, 2^20724985 is an apocalyptic number.

It is an amenable number.

20724985 is a deficient number, since it is larger than the sum of its proper divisors (4424975).

20724985 is an equidigital number, since it uses as much as digits as its factorization.

20724985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46667.

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 20724985 is about 4552.4702085791. The cubic root of 20724985 is about 274.6827636577.

The spelling of 20724985 in words is "twenty million, seven hundred twenty-four thousand, nine hundred eighty-five".