39981816 has 128 divisors (see below), whose sum is σ = 131174400. Its totient is φ = 11041920.

The previous prime is 39981811. The next prime is 39981817. The reversal of 39981816 is 61818993.

It is a super-2 number, since 2×39981816² = 3197091221315712, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39981811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 46446 + ... + 47298.

It is an arithmetic number, because the mean of its divisors is an integer number (1024800).

Almost surely, 2^39981816 is an apocalyptic number.

39981816 is a gapful number since it is divisible by the number (36) 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 39981816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (65587200).

39981816 is an abundant number, since it is smaller than the sum of its proper divisors (91192584).

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

39981816 is a wasteful number, since it uses less digits than its factorization.

39981816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 906 (or 896 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 39981816 is about 6323.1175854953. The cubic root of 39981816 is about 341.9433578093.

It can be divided in two parts, 399 and 81816, that added together give a triangular number (82215 = T₄₀₅).

The spelling of 39981816 in words is "thirty-nine million, nine hundred eighty-one thousand, eight hundred sixteen".