51690517 has 4 divisors (see below), whose sum is σ = 53087596. Its totient is φ = 50293440.

The previous prime is 51690503. The next prime is 51690539. The reversal of 51690517 is 71509615.

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 35117476 + 16573041 = 5926^2 + 4071^2 .

It is a cyclic number.

It is not a de Polignac number, because 51690517 - 2⁷ = 51690389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51600517) 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, 698484 + ... + 698557.

It is an arithmetic number, because the mean of its divisors is an integer number (13271899).

Almost surely, 2^51690517 is an apocalyptic number.

It is an amenable number.

51690517 is a deficient number, since it is larger than the sum of its proper divisors (1397079).

51690517 is a wasteful number, since it uses less digits than its factorization.

51690517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1397078.

The product of its (nonzero) digits is 9450, while the sum is 34.

The square root of 51690517 is about 7189.6117419510. The cubic root of 51690517 is about 372.5091618244.

The spelling of 51690517 in words is "fifty-one million, six hundred ninety thousand, five hundred seventeen".