51645121 has 4 divisors (see below), whose sum is σ = 56340144. Its totient is φ = 46950100.

The previous prime is 51645109. The next prime is 51645131. The reversal of 51645121 is 12154615.

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 51645121 - 2¹³ = 51636929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51645131) 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, 2347495 + ... + 2347516.

It is an arithmetic number, because the mean of its divisors is an integer number (14085036).

Almost surely, 2^51645121 is an apocalyptic number.

It is an amenable number.

51645121 is a deficient number, since it is larger than the sum of its proper divisors (4695023).

51645121 is a wasteful number, since it uses less digits than its factorization.

51645121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4695022.

The product of its digits is 1200, while the sum is 25.

The square root of 51645121 is about 7186.4539934518. The cubic root of 51645121 is about 372.4000807027.

Adding to 51645121 its reverse (12154615), we get a palindrome (63799736).

The spelling of 51645121 in words is "fifty-one million, six hundred forty-five thousand, one hundred twenty-one".