20405481 has 8 divisors (see below), whose sum is σ = 27374880. Its totient is φ = 13519872.

The previous prime is 20405479. The next prime is 20405501. The reversal of 20405481 is 18450402.

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

It is not a de Polignac number, because 20405481 - 2¹ = 20405479 is a prime.

It is a super-2 number, since 2×20405481² = 832767309682722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20405461) 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, 20376 + ... + 21353.

It is an arithmetic number, because the mean of its divisors is an integer number (3421860).

Almost surely, 2^20405481 is an apocalyptic number.

It is an amenable number.

20405481 is a deficient number, since it is larger than the sum of its proper divisors (6969399).

20405481 is a wasteful number, since it uses less digits than its factorization.

20405481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41895.

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 20405481 is about 4517.2426324031. The cubic root of 20405481 is about 273.2639104211.

Adding to 20405481 its reverse (18450402), we get a palindrome (38855883).

The spelling of 20405481 in words is "twenty million, four hundred five thousand, four hundred eighty-one".