51240065 has 4 divisors (see below), whose sum is σ = 61488084. Its totient is φ = 40992048.

The previous prime is 51240019. The next prime is 51240073. The reversal of 51240065 is 56004215.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56004215 = 5 ⋅11200843.

It can be written as a sum of positive squares in 2 ways, for example, as 9042049 + 42198016 = 3007^2 + 6496^2 .

It is a cyclic number.

It is not a de Polignac number, because 51240065 - 2⁶ = 51240001 is a prime.

It is a super-2 number, since 2×51240065² = 5251088522408450, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51240065.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5124002 + ... + 5124011.

It is an arithmetic number, because the mean of its divisors is an integer number (15372021).

Almost surely, 2^51240065 is an apocalyptic number.

It is an amenable number.

51240065 is a deficient number, since it is larger than the sum of its proper divisors (10248019).

51240065 is a wasteful number, since it uses less digits than its factorization.

51240065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10248018.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 51240065 is about 7158.2166075078. The cubic root of 51240065 is about 371.4239383403.

The spelling of 51240065 in words is "fifty-one million, two hundred forty thousand, sixty-five".