40782781 has 4 divisors (see below), whose sum is σ = 43919932. Its totient is φ = 37645632.

The previous prime is 40782773. The next prime is 40782799. The reversal of 40782781 is 18728704.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15280281 + 25502500 = 3909^2 + 5050^2 .

It is a cyclic number.

It is not a de Polignac number, because 40782781 - 2³ = 40782773 is a prime.

It is a super-2 number, since 2×40782781² = 3326470452187922, 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 40782781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40782761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1568556 + ... + 1568581.

It is an arithmetic number, because the mean of its divisors is an integer number (10979983).

Almost surely, 2^40782781 is an apocalyptic number.

It is an amenable number.

40782781 is a deficient number, since it is larger than the sum of its proper divisors (3137151).

40782781 is a wasteful number, since it uses less digits than its factorization.

40782781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3137150.

The product of its (nonzero) digits is 25088, while the sum is 37.

The square root of 40782781 is about 6386.1397573182. The cubic root of 40782781 is about 344.2116874689.

It can be divided in two parts, 4078 and 2781, that added together give a cube (6859 = 19³).

The spelling of 40782781 in words is "forty million, seven hundred eighty-two thousand, seven hundred eighty-one".