51698409 has 32 divisors (see below), whose sum is σ = 80640000. Its totient is φ = 28854144.

The previous prime is 51698407. The next prime is 51698419. The reversal of 51698409 is 90489615.

It is not a de Polignac number, because 51698409 - 2¹ = 51698407 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51698401) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 259692 + ... + 259890.

It is an arithmetic number, because the mean of its divisors is an integer number (2520000).

Almost surely, 2^51698409 is an apocalyptic number.

It is an amenable number.

51698409 is a deficient number, since it is larger than the sum of its proper divisors (28941591).

51698409 is a wasteful number, since it uses less digits than its factorization.

51698409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437.

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 51698409 is about 7190.1605684435. The cubic root of 51698409 is about 372.5281188329.

The spelling of 51698409 in words is "fifty-one million, six hundred ninety-eight thousand, four hundred nine".