402009 has 8 divisors (see below), whose sum is σ = 541632. Its totient is φ = 265200.

The previous prime is 401993. The next prime is 402023. The reversal of 402009 is 900204.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 402009 - 2⁴ = 401993 is a prime.

It is a super-2 number, since 2×402009² = 323222472162, which contains 22 as substring.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (402029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 342 + ... + 959.

It is an arithmetic number, because the mean of its divisors is an integer number (67704).

2⁴⁰²⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

402009 is a deficient number, since it is larger than the sum of its proper divisors (139623).

402009 is a wasteful number, since it uses less digits than its factorization.

402009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1407.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 402009 is about 634.0417967295. The cubic root of 402009 is about 73.8037776872.

The spelling of 402009 in words is "four hundred two thousand, nine".