20810121 has 4 divisors (see below), whose sum is σ = 27746832. Its totient is φ = 13873412.

The previous prime is 20810117. The next prime is 20810123. The reversal of 20810121 is 12101802.

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.

It is a cyclic number.

It is not a de Polignac number, because 20810121 - 2² = 20810117 is a prime.

It is a super-2 number, since 2×20810121² = 866122272069282, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20810121.

It is not an unprimeable number, because it can be changed into a prime (20810123) 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, 3468351 + ... + 3468356.

It is an arithmetic number, because the mean of its divisors is an integer number (6936708).

Almost surely, 2^20810121 is an apocalyptic number.

It is an amenable number.

20810121 is a deficient number, since it is larger than the sum of its proper divisors (6936711).

20810121 is an equidigital number, since it uses as much as digits as its factorization.

20810121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6936710.

The product of its (nonzero) digits is 32, while the sum is 15.

The square root of 20810121 is about 4561.8111534784. The cubic root of 20810121 is about 275.0583721819.

Adding to 20810121 its reverse (12101802), we get a palindrome (32911923).

The spelling of 20810121 in words is "twenty million, eight hundred ten thousand, one hundred twenty-one".