51690213 has 6 divisors (see below), whose sum is σ = 74663654. Its totient is φ = 34460136.

The previous prime is 51690179. The next prime is 51690263. The reversal of 51690213 is 31209615.

It can be written as a sum of positive squares in only one way, i.e., 28965924 + 22724289 = 5382^2 + 4767^2 .

It is not a de Polignac number, because 51690213 - 2¹⁰ = 51689189 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 (51690263) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2871670 + ... + 2871687.

Almost surely, 2^51690213 is an apocalyptic number.

It is an amenable number.

51690213 is a deficient number, since it is larger than the sum of its proper divisors (22973441).

51690213 is a wasteful number, since it uses less digits than its factorization.

51690213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5743363 (or 5743360 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 51690213 is about 7189.5906003054. The cubic root of 51690213 is about 372.5084315615.

Adding to 51690213 its reverse (31209615), we get a palindrome (82899828).

The spelling of 51690213 in words is "fifty-one million, six hundred ninety thousand, two hundred thirteen".