20408311 has 16 divisors (see below), whose sum is σ = 25809408. Its totient is φ = 15674400.

The previous prime is 20408309. The next prime is 20408341. The reversal of 20408311 is 11380402.

It is not a de Polignac number, because 20408311 - 2¹ = 20408309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20408341) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3601 + ... + 7333.

It is an arithmetic number, because the mean of its divisors is an integer number (1613088).

Almost surely, 2^20408311 is an apocalyptic number.

20408311 is a deficient number, since it is larger than the sum of its proper divisors (5401097).

20408311 is a wasteful number, since it uses less digits than its factorization.

20408311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3822.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 20408311 is about 4517.5558657309. Note that the first 3 decimals coincide. The cubic root of 20408311 is about 273.2765426663.

Adding to 20408311 its reverse (11380402), we get a palindrome (31788713).

The spelling of 20408311 in words is "twenty million, four hundred eight thousand, three hundred eleven".