38809781 has 6 divisors (see below), whose sum is σ = 39888450. Its totient is φ = 37759536.

The previous prime is 38809751. The next prime is 38809789. The reversal of 38809781 is 18790883.

It can be written as a sum of positive squares in 3 ways, for example, as 10666756 + 28143025 = 3266^2 + 5305^2 .

It is a de Polignac number, because none of the positive numbers 2^k-38809781 is a prime.

It is a super-2 number, since 2×38809781² = 3012398202535922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (38809789) 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, 12806 + ... + 15543.

It is an arithmetic number, because the mean of its divisors is an integer number (6648075).

Almost surely, 2^38809781 is an apocalyptic number.

It is an amenable number.

38809781 is a deficient number, since it is larger than the sum of its proper divisors (1078669).

38809781 is an equidigital number, since it uses as much as digits as its factorization.

38809781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28423 (or 28386 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 44.

The square root of 38809781 is about 6229.7496739436. The cubic root of 38809781 is about 338.5689011713.

The spelling of 38809781 in words is "thirty-eight million, eight hundred nine thousand, seven hundred eighty-one".