20421701 has 4 divisors (see below), whose sum is σ = 20632332. Its totient is φ = 20211072.

The previous prime is 20421697. The next prime is 20421703. The reversal of 20421701 is 10712402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10712402 = 2 ⋅5356201.

It can be written as a sum of positive squares in 2 ways, for example, as 4301476 + 16120225 = 2074^2 + 4015^2 .

It is a cyclic number.

It is not a de Polignac number, because 20421701 - 2² = 20421697 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 20421701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421703) 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, 105170 + ... + 105363.

It is an arithmetic number, because the mean of its divisors is an integer number (5158083).

Almost surely, 2^20421701 is an apocalyptic number.

It is an amenable number.

20421701 is a deficient number, since it is larger than the sum of its proper divisors (210631).

20421701 is an equidigital number, since it uses as much as digits as its factorization.

20421701 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210630.

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

The square root of 20421701 is about 4519.0376187857. The cubic root of 20421701 is about 273.3362956583.

The spelling of 20421701 in words is "twenty million, four hundred twenty-one thousand, seven hundred one".