51690685 has 4 divisors (see below), whose sum is σ = 62028828. Its totient is φ = 41352544.

The previous prime is 51690679. The next prime is 51690721. The reversal of 51690685 is 58609615.

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 20921476 + 30769209 = 4574^2 + 5547^2 .

It is a cyclic number.

It is not a de Polignac number, because 51690685 - 2³ = 51690677 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 5169064 + ... + 5169073.

It is an arithmetic number, because the mean of its divisors is an integer number (15507207).

Almost surely, 2^51690685 is an apocalyptic number.

It is an amenable number.

51690685 is a deficient number, since it is larger than the sum of its proper divisors (10338143).

51690685 is a wasteful number, since it uses less digits than its factorization.

51690685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10338142.

The product of its (nonzero) digits is 64800, while the sum is 40.

The square root of 51690685 is about 7189.6234254653. The cubic root of 51690685 is about 372.5095653896.

The spelling of 51690685 in words is "fifty-one million, six hundred ninety thousand, six hundred eighty-five".