20724101 has 4 divisors (see below), whose sum is σ = 20733900. Its totient is φ = 20714304.

The previous prime is 20724097. The next prime is 20724161. The reversal of 20724101 is 10142702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 10142702 = 2 ⋅5071351.

It can be written as a sum of positive squares in 2 ways, for example, as 16728100 + 3996001 = 4090^2 + 1999^2 .

It is a cyclic number.

It is not a de Polignac number, because 20724101 - 2² = 20724097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20724101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20724161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 266 + ... + 6443.

It is an arithmetic number, because the mean of its divisors is an integer number (5183475).

Almost surely, 2^20724101 is an apocalyptic number.

It is an amenable number.

20724101 is a deficient number, since it is larger than the sum of its proper divisors (9799).

20724101 is an equidigital number, since it uses as much as digits as its factorization.

20724101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9798.

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 20724101 is about 4552.3731173971. The cubic root of 20724101 is about 274.6788581781.

Adding to 20724101 its reverse (10142702), we get a palindrome (30866803).

The spelling of 20724101 in words is "twenty million, seven hundred twenty-four thousand, one hundred one".