40399920 has 120 divisors (see below), whose sum is σ = 148039632. Its totient is φ = 9792000.

The previous prime is 40399907. The next prime is 40399921. The reversal of 40399920 is 2999304.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (40399921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5370 + ... + 10470.

Almost surely, 2^40399920 is an apocalyptic number.

40399920 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 40399920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74019816).

40399920 is an abundant number, since it is smaller than the sum of its proper divisors (107639712).

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

40399920 is a wasteful number, since it uses less digits than its factorization.

40399920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5131 (or 5122 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The square root of 40399920 is about 6356.0931396574. The cubic root of 40399920 is about 343.1311678348.

The spelling of 40399920 in words is "forty million, three hundred ninety-nine thousand, nine hundred twenty".