402021540 has 72 divisors (see below), whose sum is σ = 1224961920. Its totient is φ = 106722624.

The previous prime is 402021527. The next prime is 402021541. The reversal of 402021540 is 45120204.

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

It is not an unprimeable number, because it can be changed into a prime (402021541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35941 + ... + 45779.

It is an arithmetic number, because the mean of its divisors is an integer number (17013360).

Almost surely, 2^402021540 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 402021540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (612480960).

402021540 is an abundant number, since it is smaller than the sum of its proper divisors (822940380).

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

402021540 is a wasteful number, since it uses less digits than its factorization.

402021540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10081 (or 10076 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 402021540 is about 20050.4748073456. The cubic root of 402021540 is about 738.0454507448.

Adding to 402021540 its reverse (45120204), we get a palindrome (447141744).

The spelling of 402021540 in words is "four hundred two million, twenty-one thousand, five hundred forty".