20720101 has 4 divisors (see below), whose sum is σ = 21004012. Its totient is φ = 20436192.

The previous prime is 20720087. The next prime is 20720107. The reversal of 20720101 is 10102702.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6477025 + 14243076 = 2545^2 + 3774^2 .

It is a cyclic number.

It is not a de Polignac number, because 20720101 - 2⁷ = 20719973 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 (20720107) 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, 141846 + ... + 141991.

It is an arithmetic number, because the mean of its divisors is an integer number (5251003).

Almost surely, 2^20720101 is an apocalyptic number.

It is an amenable number.

20720101 is a deficient number, since it is larger than the sum of its proper divisors (283911).

20720101 is an equidigital number, since it uses as much as digits as its factorization.

20720101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283910.

The product of its (nonzero) digits is 28, while the sum is 13.

The square root of 20720101 is about 4551.9337648960. The cubic root of 20720101 is about 274.6611849366.

Adding to 20720101 its reverse (10102702), we get a palindrome (30822803).

The spelling of 20720101 in words is "twenty million, seven hundred twenty thousand, one hundred one".