51428009 has 4 divisors (see below), whose sum is σ = 54453204. Its totient is φ = 48402816.

The previous prime is 51427997. The next prime is 51428017. The reversal of 51428009 is 90082415.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90082415 = 5 ⋅18016483.

It can be written as a sum of positive squares in 2 ways, for example, as 37552384 + 13875625 = 6128^2 + 3725^2 .

It is a cyclic number.

It is not a de Polignac number, because 51428009 - 2¹² = 51423913 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (51428029) 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, 1512572 + ... + 1512605.

It is an arithmetic number, because the mean of its divisors is an integer number (13613301).

Almost surely, 2^51428009 is an apocalyptic number.

It is an amenable number.

51428009 is a deficient number, since it is larger than the sum of its proper divisors (3025195).

51428009 is a wasteful number, since it uses less digits than its factorization.

51428009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3025194.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 51428009 is about 7171.3324424405. The cubic root of 51428009 is about 371.8775009035.

The spelling of 51428009 in words is "fifty-one million, four hundred twenty-eight thousand, nine".