40000000 has 80 divisors (see below), whose sum is σ = 99902088.
Its totient is φ = 16000000.
The previous prime is 39999983. The next prime is 40000003. The reversal of 40000000 is 4.
It is a powerful number, because all its prime factors have an exponent greater than 1
and also an Achilles number because it is not a perfect power.
It can be written as a sum of positive squares in 4 ways, for example, as 24127744 + 15872256 = 4912^2 + 3984^2
It is a tau number, because it is divible by the number of its divisors (80).
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 nialpdrome in base 10.
It is not an unprimeable number, because it can be changed into a prime (40000003) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7999998 + ... + 8000002.
Almost surely, 240000000 is an apocalyptic number.
40000000 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 40000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49951044).
40000000 is an abundant number, since it is smaller than the sum of its proper divisors (59902088).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
40000000 is an frugal number, since it uses more digits than its factorization.
40000000 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 53 (or 7 counting only the distinct ones).
The product of its (nonzero) digits is 4, while the sum is 4.
The square root of 40000000 is about 6324.5553203368.
Note that the first 3 decimals coincide.
The cubic root of 40000000 is about 341.9951893353.
The spelling of 40000000 in words is "forty million", and thus it is an aban number, an eban number, and an uban number.