188440681 has 12 divisors (see below), whose sum is σ = 223063876. Its totient is φ = 158130720.

The previous prime is 188440669. The next prime is 188440697. The reversal of 188440681 is 186044881.

It is a happy number.

188440681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 125888400 + 62552281 = 11220^2 + 7909^2 .

It is not a de Polignac number, because 188440681 - 2²¹ = 186343529 is a prime.

It is a super-2 number, since 2×188440681² = 71019780511487522, which contains 22 as substring.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (188440621) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 58326 + ... + 61471.

Almost surely, 2^188440681 is an apocalyptic number.

188440681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

188440681 is a deficient number, since it is larger than the sum of its proper divisors (34623195).

188440681 is a wasteful number, since it uses less digits than its factorization.

188440681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119832 (or 119821 counting only the distinct ones).

The product of its (nonzero) digits is 49152, while the sum is 40.

The square root of 188440681 is about 13727.3697772006. The cubic root of 188440681 is about 573.3126903135.

The spelling of 188440681 in words is "one hundred eighty-eight million, four hundred forty thousand, six hundred eighty-one".