51001409 has 4 divisors (see below), whose sum is σ = 51138516. Its totient is φ = 50864304.

The previous prime is 51001381. The next prime is 51001421. The reversal of 51001409 is 90410015.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90410015 = 5 ⋅18082003.

It can be written as a sum of positive squares in 2 ways, for example, as 11751184 + 39250225 = 3428^2 + 6265^2 .

It is a cyclic number.

It is not a de Polignac number, because 51001409 - 2¹⁶ = 50935873 is a prime.

It is a super-2 number, since 2×51001409² = 5202287439970562, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51001469) 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, 67994 + ... + 68739.

It is an arithmetic number, because the mean of its divisors is an integer number (12784629).

Almost surely, 2^51001409 is an apocalyptic number.

It is an amenable number.

51001409 is a deficient number, since it is larger than the sum of its proper divisors (137107).

51001409 is a wasteful number, since it uses less digits than its factorization.

51001409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137106.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 51001409 is about 7141.5270775934. The cubic root of 51001409 is about 370.8463920439.

The spelling of 51001409 in words is "fifty-one million, one thousand, four hundred nine".