402400020 has 144 divisors (see below), whose sum is σ = 1268245440. Its totient is φ = 95208960.

The previous prime is 402399997. The next prime is 402400039. The reversal of 402400020 is 20004204.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 402399969 and 402400005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 311536 + ... + 312824.

It is an arithmetic number, because the mean of its divisors is an integer number (8807260).

Almost surely, 2^402400020 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 402400020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (634122720).

402400020 is an abundant number, since it is smaller than the sum of its proper divisors (865845420).

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

402400020 is a wasteful number, since it uses less digits than its factorization.

402400020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1366 (or 1353 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 12.

The square root of 402400020 is about 20059.9107674984. The cubic root of 402400020 is about 738.2769871185.

Adding to 402400020 its reverse (20004204), we get a palindrome (422404224).

The spelling of 402400020 in words is "four hundred two million, four hundred thousand, twenty".