20400507 has 12 divisors (see below), whose sum is σ = 29872024. Its totient is φ = 13413600.

The previous prime is 20400481. The next prime is 20400521. The reversal of 20400507 is 70500402.

It is a happy number.

It is not a de Polignac number, because 20400507 - 2¹¹ = 20398459 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20400507.

It is not an unprimeable number, because it can be changed into a prime (20400577) 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, 14869 + ... + 16182.

Almost surely, 2^20400507 is an apocalyptic number.

20400507 is a deficient number, since it is larger than the sum of its proper divisors (9471517).

20400507 is a wasteful number, since it uses less digits than its factorization.

20400507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31130 (or 31127 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 18.

The square root of 20400507 is about 4516.6920417491. The cubic root of 20400507 is about 273.2417051920.

Adding to 20400507 its reverse (70500402), we get a palindrome (90900909).

The spelling of 20400507 in words is "twenty million, four hundred thousand, five hundred seven".