402006640 has 80 divisors (see below), whose sum is σ = 1094304960. Its totient is φ = 134461440.

The previous prime is 402006629. The next prime is 402006659. The reversal of 402006640 is 46600204.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14206 + ... + 31714.

It is an arithmetic number, because the mean of its divisors is an integer number (13678812).

Almost surely, 2^402006640 is an apocalyptic number.

402006640 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 402006640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (547152480).

402006640 is an abundant number, since it is smaller than the sum of its proper divisors (692298320).

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

402006640 is a wasteful number, since it uses less digits than its factorization.

402006640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17570 (or 17564 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 402006640 is about 20050.1032416295. The cubic root of 402006640 is about 738.0363326487.

Adding to 402006640 its reverse (46600204), we get a palindrome (448606844).

The spelling of 402006640 in words is "four hundred two million, six thousand, six hundred forty".