40981781 has 4 divisors (see below), whose sum is σ = 43392492. Its totient is φ = 38571072.

The previous prime is 40981771. The next prime is 40981793. The reversal of 40981781 is 18718904.

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 29866225 + 11115556 = 5465^2 + 3334^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40981781 is a prime.

It is a super-2 number, since 2×40981781² = 3359012747863922, 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 (40981771) 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, 1205330 + ... + 1205363.

It is an arithmetic number, because the mean of its divisors is an integer number (10848123).

Almost surely, 2^40981781 is an apocalyptic number.

It is an amenable number.

40981781 is a deficient number, since it is larger than the sum of its proper divisors (2410711).

40981781 is a wasteful number, since it uses less digits than its factorization.

40981781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2410710.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 40981781 is about 6401.7014144679. The cubic root of 40981781 is about 344.7706408044.

The spelling of 40981781 in words is "forty million, nine hundred eighty-one thousand, seven hundred eighty-one".