402309 has 6 divisors (see below), whose sum is σ = 581126. Its totient is φ = 268200.

The previous prime is 402307. The next prime is 402313. The reversal of 402309 is 903204.

It can be written as a sum of positive squares in only one way, i.e., 202500 + 199809 = 450^2 + 447^2 .

It is not a de Polignac number, because 402309 - 2¹ = 402307 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 402291 and 402300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402307) 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, 22342 + ... + 22359.

2⁴⁰²³⁰⁹ is an apocalyptic number.

It is an amenable number.

402309 is a deficient number, since it is larger than the sum of its proper divisors (178817).

402309 is a wasteful number, since it uses less digits than its factorization.

402309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44707 (or 44704 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 402309 is about 634.2783300728. The cubic root of 402309 is about 73.8221318600.

The spelling of 402309 in words is "four hundred two thousand, three hundred nine".