20400641 has 4 divisors (see below), whose sum is σ = 20409792. Its totient is φ = 20391492.

The previous prime is 20400637. The next prime is 20400671. The reversal of 20400641 is 14600402.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20400641 - 2² = 20400637 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20400631) 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, 1196 + ... + 6498.

It is an arithmetic number, because the mean of its divisors is an integer number (5102448).

Almost surely, 2^20400641 is an apocalyptic number.

It is an amenable number.

20400641 is a deficient number, since it is larger than the sum of its proper divisors (9151).

20400641 is an equidigital number, since it uses as much as digits as its factorization.

20400641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9150.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 20400641 is about 4516.7068755898. The cubic root of 20400641 is about 273.2423034501.

The spelling of 20400641 in words is "twenty million, four hundred thousand, six hundred forty-one".