40781381 has 4 divisors (see below), whose sum is σ = 40902732. Its totient is φ = 40660032.

The previous prime is 40781341. The next prime is 40781393. The reversal of 40781381 is 18318704.

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 24661156 + 16120225 = 4966^2 + 4015^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40781381 is a prime.

It is a super-2 number, since 2×40781381² = 3326242072534322, 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 (40781311) 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, 60170 + ... + 60843.

It is an arithmetic number, because the mean of its divisors is an integer number (10225683).

Almost surely, 2^40781381 is an apocalyptic number.

It is an amenable number.

40781381 is a deficient number, since it is larger than the sum of its proper divisors (121351).

40781381 is a wasteful number, since it uses less digits than its factorization.

40781381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121350.

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 40781381 is about 6386.0301439940. The cubic root of 40781381 is about 344.2077486998.

The spelling of 40781381 in words is "forty million, seven hundred eighty-one thousand, three hundred eighty-one".