20421101 has 4 divisors (see below), whose sum is σ = 20443104. Its totient is φ = 20399100.

The previous prime is 20421073. The next prime is 20421103. The reversal of 20421101 is 10112402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 10112402 = 2 ⋅5056201.

It is a cyclic number.

It is not a de Polignac number, because 20421101 - 2¹⁴ = 20404717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421103) 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, 9545 + ... + 11486.

It is an arithmetic number, because the mean of its divisors is an integer number (5110776).

Almost surely, 2^20421101 is an apocalyptic number.

It is an amenable number.

20421101 is a deficient number, since it is larger than the sum of its proper divisors (22003).

20421101 is an equidigital number, since it uses as much as digits as its factorization.

20421101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22002.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 20421101 is about 4518.9712324820. The cubic root of 20421101 is about 273.3336187121. Note that the first 3 decimals are identical.

Adding to 20421101 its reverse (10112402), we get a palindrome (30533503).

The spelling of 20421101 in words is "twenty million, four hundred twenty-one thousand, one hundred one".