20506401 has 12 divisors (see below), whose sum is σ = 29954340. Its totient is φ = 13516800.

The previous prime is 20506397. The next prime is 20506417. The reversal of 20506401 is 10460502.

It is a happy number.

20506401 is a `hidden beast` number, since 20 + 5 + 0 + 640 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14630625 + 5875776 = 3825^2 + 2424^2 .

It is not a de Polignac number, because 20506401 - 2² = 20506397 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20506441) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12000 + ... + 13601.

It is an arithmetic number, because the mean of its divisors is an integer number (2496195).

Almost surely, 2^20506401 is an apocalyptic number.

It is an amenable number.

20506401 is a deficient number, since it is larger than the sum of its proper divisors (9447939).

20506401 is a wasteful number, since it uses less digits than its factorization.

20506401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25696 (or 25693 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20506401 is about 4528.3993860966. The cubic root of 20506401 is about 273.7136662856.

Adding to 20506401 its reverse (10460502), we get a palindrome (30966903).

The spelling of 20506401 in words is "twenty million, five hundred six thousand, four hundred one".