402840 has 64 divisors (see below), whose sum is σ = 1346400. Its totient is φ = 107136.

The previous prime is 402823. The next prime is 402847. The reversal of 402840 is 48204.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402847) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 894 + ... + 1266.

2⁴⁰²⁸⁴⁰ is an apocalyptic number.

402840 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 402840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (673200).

402840 is an abundant number, since it is smaller than the sum of its proper divisors (943560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

402840 is a wasteful number, since it uses less digits than its factorization.

402840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393 (or 383 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 402840 is about 634.6967779972. The cubic root of 402840 is about 73.8545963905.

The spelling of 402840 in words is "four hundred two thousand, eight hundred forty".