42388381 has 6 divisors (see below), whose sum is σ = 49308990. Its totient is φ = 36332856.

The previous prime is 42388331. The next prime is 42388403. The reversal of 42388381 is 18388324.

It can be written as a sum of positive squares in only one way, i.e., 42380100 + 8281 = 6510^2 + 91^2 .

It is not a de Polignac number, because 42388381 - 2⁹ = 42387869 is a prime.

It is a super-2 number, since 2×42388381² = 3593549687602322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 42388381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42388331) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 432486 + ... + 432583.

It is an arithmetic number, because the mean of its divisors is an integer number (8218165).

Almost surely, 2^42388381 is an apocalyptic number.

It is an amenable number.

42388381 is a deficient number, since it is larger than the sum of its proper divisors (6920609).

42388381 is an equidigital number, since it uses as much as digits as its factorization.

42388381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 865083 (or 865076 counting only the distinct ones).

The product of its digits is 36864, while the sum is 37.

The square root of 42388381 is about 6510.6359904390. The cubic root of 42388381 is about 348.6708253270.

It can be divided in two parts, 423 and 88381, that added together give a square (88804 = 298²).

The spelling of 42388381 in words is "forty-two million, three hundred eighty-eight thousand, three hundred eighty-one".