20145281 has 8 divisors (see below), whose sum is σ = 22157184. Its totient is φ = 18199440.

The previous prime is 20145277. The next prime is 20145313. The reversal of 20145281 is 18254102.

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 20145281 - 2² = 20145277 is a prime.

It is a super-2 number, since 2×20145281² = 811664693137922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20145241) 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, 15875 + ... + 17096.

It is an arithmetic number, because the mean of its divisors is an integer number (2769648).

Almost surely, 2^20145281 is an apocalyptic number.

It is an amenable number.

20145281 is a deficient number, since it is larger than the sum of its proper divisors (2011903).

20145281 is a wasteful number, since it uses less digits than its factorization.

20145281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33031.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 20145281 is about 4488.3494739158. The cubic root of 20145281 is about 272.0974321149.

Adding to 20145281 its reverse (18254102), we get a palindrome (38399383).

The spelling of 20145281 in words is "twenty million, one hundred forty-five thousand, two hundred eighty-one".