20151281 has 4 divisors (see below), whose sum is σ = 20175600. Its totient is φ = 20126964.

The previous prime is 20151277. The next prime is 20151293. The reversal of 20151281 is 18215102.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20151281 - 2² = 20151277 is a prime.

It is a super-2 number, since 2×20151281² = 812148251881922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20151221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10871 + ... + 12588.

It is an arithmetic number, because the mean of its divisors is an integer number (5043900).

Almost surely, 2^20151281 is an apocalyptic number.

It is an amenable number.

20151281 is a deficient number, since it is larger than the sum of its proper divisors (24319).

20151281 is an equidigital number, since it uses as much as digits as its factorization.

20151281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24318.

The product of its (nonzero) digits is 160, while the sum is 20.

The square root of 20151281 is about 4489.0178213057. The cubic root of 20151281 is about 272.1244429492.

Subtracting from 20151281 its product of nonzero digits (160), we obtain a 4-th power (20151121 = 67⁴).

Adding to 20151281 its reverse (18215102), we get a palindrome (38366383).

The spelling of 20151281 in words is "twenty million, one hundred fifty-one thousand, two hundred eighty-one".