39997818 has 72 divisors (see below), whose sum is σ = 102035700. Its totient is φ = 11289600.

The previous prime is 39997813. The next prime is 39997823. The reversal of 39997818 is 81879993.

It is an interprime number because it is at equal distance from previous prime (39997813) and next prime (39997823).

It can be written as a sum of positive squares in 2 ways, for example, as 35319249 + 4678569 = 5943^2 + 2163^2 .

It is a super-2 number, since 2×39997818² = 3199650889522248, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (39997813) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 88858 + ... + 89306.

Almost surely, 2^39997818 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 39997818, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51017850).

39997818 is an abundant number, since it is smaller than the sum of its proper divisors (62037882).

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

39997818 is a wasteful number, since it uses less digits than its factorization.

39997818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 572 (or 562 counting only the distinct ones).

The product of its digits is 979776, while the sum is 54.

The square root of 39997818 is about 6324.3828157378. The cubic root of 39997818 is about 341.9889706097.

The spelling of 39997818 in words is "thirty-nine million, nine hundred ninety-seven thousand, eight hundred eighteen".