20400406 has 16 divisors (see below), whose sum is σ = 33267024. Its totient is φ = 9326304.

The previous prime is 20400377. The next prime is 20400421. The reversal of 20400406 is 60400402.

It is a self number, because there is not a number n which added to its sum of digits gives 20400406.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 885 + ... + 6448.

It is an arithmetic number, because the mean of its divisors is an integer number (2079189).

Almost surely, 2^20400406 is an apocalyptic number.

20400406 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

20400406 is a deficient number, since it is larger than the sum of its proper divisors (12866618).

20400406 is a wasteful number, since it uses less digits than its factorization.

20400406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7455.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 20400406 is about 4516.6808609863. The cubic root of 20400406 is about 273.2412542643.

Adding to 20400406 its reverse (60400402), we get a palindrome (80800808).

The spelling of 20400406 in words is "twenty million, four hundred thousand, four hundred six".