20751121 has 4 divisors (see below), whose sum is σ = 21420544. Its totient is φ = 20081700.

The previous prime is 20751119. The next prime is 20751127. The reversal of 20751121 is 12115702.

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 20751121 - 2¹ = 20751119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20751127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 334665 + ... + 334726.

It is an arithmetic number, because the mean of its divisors is an integer number (5355136).

Almost surely, 2^20751121 is an apocalyptic number.

It is an amenable number.

20751121 is a deficient number, since it is larger than the sum of its proper divisors (669423).

20751121 is an equidigital number, since it uses as much as digits as its factorization.

20751121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 669422.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 20751121 is about 4555.3398336458. The cubic root of 20751121 is about 274.7981814010.

Adding to 20751121 its reverse (12115702), we get a palindrome (32866823).

The spelling of 20751121 in words is "twenty million, seven hundred fifty-one thousand, one hundred twenty-one".