20281251 has 8 divisors (see below), whose sum is σ = 27670720. Its totient is φ = 13206312.

The previous prime is 20281241. The next prime is 20281253. The reversal of 20281251 is 15218202.

It is a happy number.

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

It is not a de Polignac number, because 20281251 - 2⁷ = 20281123 is a prime.

It is a super-2 number, since 2×20281251² = 822658284250002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20281253) 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, 78481 + ... + 78738.

It is an arithmetic number, because the mean of its divisors is an integer number (3458840).

Almost surely, 2^20281251 is an apocalyptic number.

20281251 is a deficient number, since it is larger than the sum of its proper divisors (7389469).

20281251 is a wasteful number, since it uses less digits than its factorization.

20281251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157265.

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 20281251 is about 4503.4709946884. The cubic root of 20281251 is about 272.7082312665.

Adding to 20281251 its reverse (15218202), we get a palindrome (35499453).

The spelling of 20281251 in words is "twenty million, two hundred eighty-one thousand, two hundred fifty-one".