20401331 has 4 divisors (see below), whose sum is σ = 20611752. Its totient is φ = 20190912.

The previous prime is 20401321. The next prime is 20401333. The reversal of 20401331 is 13310402.

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

It is a cyclic number.

It is not a de Polignac number, because 20401331 - 2¹⁰ = 20400307 is a prime.

It is a super-2 number, since 2×20401331² = 832428613143122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20401333) 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, 105065 + ... + 105258.

It is an arithmetic number, because the mean of its divisors is an integer number (5152938).

Almost surely, 2^20401331 is an apocalyptic number.

20401331 is a deficient number, since it is larger than the sum of its proper divisors (210421).

20401331 is an equidigital number, since it uses as much as digits as its factorization.

20401331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210420.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 20401331 is about 4516.7832580278. The cubic root of 20401331 is about 273.2453839916.

Adding to 20401331 its reverse (13310402), we get a palindrome (33711733).

The spelling of 20401331 in words is "twenty million, four hundred one thousand, three hundred thirty-one".