666402438 has 64 divisors (see below), whose sum is σ = 1479389184. Its totient is φ = 198816000.

The previous prime is 666402419. The next prime is 666402461. The reversal of 666402438 is 834204666.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a junction number, because it is equal to n+sod(n) for n = 666402396 and 666402405.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 610273 + ... + 611363.

It is an arithmetic number, because the mean of its divisors is an integer number (23115456).

Almost surely, 2^666402438 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666402438, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (739694592).

666402438 is an abundant number, since it is smaller than the sum of its proper divisors (812986746).

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

666402438 is a wasteful number, since it uses less digits than its factorization.

666402438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1341.

The product of its (nonzero) digits is 165888, while the sum is 39.

The square root of 666402438 is about 25814.7717014891. The cubic root of 666402438 is about 873.4650369846.

The spelling of 666402438 in words is "six hundred sixty-six million, four hundred two thousand, four hundred thirty-eight".