51505745 has 4 divisors (see below), whose sum is σ = 61806900. Its totient is φ = 41204592.

The previous prime is 51505703. The next prime is 51505759. The reversal of 51505745 is 54750515.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54750515 = 5 ⋅10950103.

It can be written as a sum of positive squares in 2 ways, for example, as 12054784 + 39450961 = 3472^2 + 6281^2 .

It is a cyclic number.

It is not a de Polignac number, because 51505745 - 2⁶ = 51505681 is a prime.

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, 5150570 + ... + 5150579.

It is an arithmetic number, because the mean of its divisors is an integer number (15451725).

Almost surely, 2^51505745 is an apocalyptic number.

It is an amenable number.

51505745 is a deficient number, since it is larger than the sum of its proper divisors (10301155).

51505745 is a wasteful number, since it uses less digits than its factorization.

51505745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10301154.

The product of its (nonzero) digits is 17500, while the sum is 32.

The square root of 51505745 is about 7176.7503091580. The cubic root of 51505745 is about 372.0647770381.

The spelling of 51505745 in words is "fifty-one million, five hundred five thousand, seven hundred forty-five".