43155391 has 4 divisors (see below), whose sum is σ = 43420312. Its totient is φ = 42890472.

The previous prime is 43155377. The next prime is 43155419. The reversal of 43155391 is 19355134.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19355134 = 2 ⋅9677567.

It is a cyclic number.

It is not a de Polignac number, because 43155391 - 2⁷ = 43155263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43155311) 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, 132216 + ... + 132541.

It is an arithmetic number, because the mean of its divisors is an integer number (10855078).

Almost surely, 2^43155391 is an apocalyptic number.

43155391 is a deficient number, since it is larger than the sum of its proper divisors (264921).

43155391 is a wasteful number, since it uses less digits than its factorization.

43155391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 264920.

The product of its digits is 8100, while the sum is 31.

The square root of 43155391 is about 6569.2762919518. The cubic root of 43155391 is about 350.7613115204.

The spelling of 43155391 in words is "forty-three million, one hundred fifty-five thousand, three hundred ninety-one".