43401781 has 4 divisors (see below), whose sum is σ = 43429932. Its totient is φ = 43373632.

The previous prime is 43401769. The next prime is 43401791. The reversal of 43401781 is 18710434.

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 3837681 + 39564100 = 1959^2 + 6290^2 .

It is a cyclic number.

It is not a de Polignac number, because 43401781 - 2⁷ = 43401653 is a prime.

It is a super-2 number, since 2×43401781² = 3767429187943922, 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 (43401751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11620 + ... + 14893.

It is an arithmetic number, because the mean of its divisors is an integer number (10857483).

Almost surely, 2^43401781 is an apocalyptic number.

It is an amenable number.

43401781 is a deficient number, since it is larger than the sum of its proper divisors (28151).

43401781 is a wasteful number, since it uses less digits than its factorization.

43401781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28150.

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 43401781 is about 6588.0028081354. The cubic root of 43401781 is about 351.4275869007.

The spelling of 43401781 in words is "forty-three million, four hundred one thousand, seven hundred eighty-one".