40000 has 35 divisors (see below), whose sum is σ = 99187.
Its totient is φ = 16000.
The previous prime is 39989. The next prime is 40009. The reversal of 40000 is 4.
40000 = T199 + T200.
The square root of 40000 is 200.
It is a perfect power (a square), and thus also a powerful number.
40000 is nontrivially palindromic in base 7.
40000 is an esthetic number in base 15, because in such base its adjacent digits differ by 1.
It can be written as a sum of positive squares in 2 ways, for example, as 3136 + 36864 = 56^2 + 192^2
It is an ABA number since it can be written as A⋅BA, here for A=4, B=10.
It is a Harshad number since it is a multiple of its sum of digits (4).
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
It is a Duffinian number.
It is a nialpdrome in base 10.
It is a zygodrome in base 7.
It is not an unprimeable number, because it can be changed into a prime (40009) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (5) of ones.
It is a polite number, since it can be written in 4 ways as a sum of consecutive naturals, for example, 7998 + ... + 8002.
240000 is an apocalyptic number.
40000 is a gapful number since it is divisible by the number (40) formed by its first and last digit.
40000 is the 200-th square number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 40000
40000 is an abundant number, since it is smaller than the sum of its proper divisors (59187).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
40000 is an frugal number, since it uses more digits than its factorization.
40000 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 32 (or 7 counting only the distinct ones).
The product of its (nonzero) digits is 4, while the sum is 4.
The cubic root of 40000 is about 34.1995189335.
The spelling of 40000 in words is "forty thousand", and thus it is an eban number and an iban number.