20401121 has 4 divisors (see below), whose sum is σ = 21970452. Its totient is φ = 18831792.

The previous prime is 20401111. The next prime is 20401127. The reversal of 20401121 is 12110402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12110402 = 2 ⋅6055201.

It can be written as a sum of positive squares in 2 ways, for example, as 1600225 + 18800896 = 1265^2 + 4336^2 .

It is a cyclic number.

It is not a de Polignac number, because 20401121 - 2⁶ = 20401057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20401127) 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, 784646 + ... + 784671.

It is an arithmetic number, because the mean of its divisors is an integer number (5492613).

Almost surely, 2^20401121 is an apocalyptic number.

It is an amenable number.

20401121 is a deficient number, since it is larger than the sum of its proper divisors (1569331).

20401121 is a wasteful number, since it uses less digits than its factorization.

20401121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1569330.

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

The square root of 20401121 is about 4516.7600113356. The cubic root of 20401121 is about 273.2444464428.

Adding to 20401121 its reverse (12110402), we get a palindrome (32511523).

The spelling of 20401121 in words is "twenty million, four hundred one thousand, one hundred twenty-one".