42640400 has 90 divisors (see below), whose sum is σ = 112731066. Its totient is φ = 15488000.

The previous prime is 42640393. The next prime is 42640417. The reversal of 42640400 is 404624.

It can be written as a sum of positive squares in 3 ways, for example, as 234256 + 42406144 = 484^2 + 6512^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 47960 + ... + 48840.

Almost surely, 2^42640400 is an apocalyptic number.

42640400 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 42640400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (56365533).

42640400 is an abundant number, since it is smaller than the sum of its proper divisors (70090666).

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

42640400 is a wasteful number, since it uses less digits than its factorization.

42640400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 921 (or 899 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 42640400 is about 6529.9617150486. The cubic root of 42640400 is about 349.3604647783.

The spelling of 42640400 in words is "forty-two million, six hundred forty thousand, four hundred".