400037840 has 20 divisors (see below), whose sum is σ = 930088164. Its totient is φ = 160015104.

The previous prime is 400037819. The next prime is 400037843. The reversal of 400037840 is 48730004.

It can be written as a sum of positive squares in 2 ways, for example, as 47499664 + 352538176 = 6892^2 + 18776^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400037843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2500157 + ... + 2500316.

Almost surely, 2^400037840 is an apocalyptic number.

400037840 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

400037840 is an abundant number, since it is smaller than the sum of its proper divisors (530050324).

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

400037840 is a wasteful number, since it uses less digits than its factorization.

400037840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5000486 (or 5000480 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 400037840 is about 20000.9459776282. The cubic root of 400037840 is about 736.8295329541.

Adding to 400037840 its reverse (48730004), we get a palindrome (448767844).

The spelling of 400037840 in words is "four hundred million, thirty-seven thousand, eight hundred forty".