40017920 has 56 divisors (see below), whose sum is σ = 96135444. Its totient is φ = 15990784.

The previous prime is 40017899. The next prime is 40017947. The reversal of 40017920 is 2971004.

It can be written as a sum of positive squares in 2 ways, for example, as 38539264 + 1478656 = 6208^2 + 1216^2 .

It is a super-2 number, since 2×40017920² = 3202867842252800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40472 + ... + 41448.

Almost surely, 2^40017920 is an apocalyptic number.

40017920 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 40017920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48067722).

40017920 is an abundant number, since it is smaller than the sum of its proper divisors (56117524).

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

40017920 is an frugal number, since it uses more digits than its factorization.

40017920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1008 (or 984 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 40017920 is about 6325.9718620936. The cubic root of 40017920 is about 342.0462529922.

Adding to 40017920 its reverse (2971004), we get a palindrome (42988924).

The spelling of 40017920 in words is "forty million, seventeen thousand, nine hundred twenty".