20408551 has 8 divisors (see below), whose sum is σ = 22017744. Its totient is φ = 18844800.

The previous prime is 20408543. The next prime is 20408561. The reversal of 20408551 is 15580402.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20408551 - 2³ = 20408543 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 (20408561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10425 + ... + 12226.

It is an arithmetic number, because the mean of its divisors is an integer number (2752218).

Almost surely, 2^20408551 is an apocalyptic number.

20408551 is a deficient number, since it is larger than the sum of its proper divisors (1609193).

20408551 is a wasteful number, since it uses less digits than its factorization.

20408551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22721.

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 20408551 is about 4517.5824286890. The cubic root of 20408551 is about 273.2776138984.

Adding to 20408551 its reverse (15580402), we get a palindrome (35988953).

The spelling of 20408551 in words is "twenty million, four hundred eight thousand, five hundred fifty-one".