51897809 has 4 divisors (see below), whose sum is σ = 52100004. Its totient is φ = 51695616.

The previous prime is 51897803. The next prime is 51897829. The reversal of 51897809 is 90879815.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 47997184 + 3900625 = 6928^2 + 1975^2 .

It is a cyclic number.

It is not a de Polignac number, because 51897809 - 2⁴ = 51897793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51897803) 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, 100712 + ... + 101225.

It is an arithmetic number, because the mean of its divisors is an integer number (13025001).

Almost surely, 2^51897809 is an apocalyptic number.

It is an amenable number.

51897809 is a deficient number, since it is larger than the sum of its proper divisors (202195).

51897809 is a wasteful number, since it uses less digits than its factorization.

51897809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202194.

The product of its (nonzero) digits is 181440, while the sum is 47.

The square root of 51897809 is about 7204.0133953235. The cubic root of 51897809 is about 373.0064495383.

The spelling of 51897809 in words is "fifty-one million, eight hundred ninety-seven thousand, eight hundred nine".