20161251 has 16 divisors (see below), whose sum is σ = 32584320. Its totient is φ = 12218760.

The previous prime is 20161243. The next prime is 20161277. The reversal of 20161251 is 15216102.

20161251 is a `hidden beast` number, since 2 + 0 + 1 + 612 + 51 = 666.

It is not a de Polignac number, because 20161251 - 2³ = 20161243 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20161241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33645 + ... + 34238.

It is an arithmetic number, because the mean of its divisors is an integer number (2036520).

Almost surely, 2^20161251 is an apocalyptic number.

20161251 is a deficient number, since it is larger than the sum of its proper divisors (12423069).

20161251 is a wasteful number, since it uses less digits than its factorization.

20161251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67903 (or 67897 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 20161251 is about 4490.1281718900. The cubic root of 20161251 is about 272.1693140979.

Adding to 20161251 its reverse (15216102), we get a palindrome (35377353).

The spelling of 20161251 in words is "twenty million, one hundred sixty-one thousand, two hundred fifty-one".