43137981 has 8 divisors (see below), whose sum is σ = 63908160. Its totient is φ = 28758636.

The previous prime is 43137971. The next prime is 43137989. The reversal of 43137981 is 18973134.

It is a happy number.

It is not a de Polignac number, because 43137981 - 2⁶ = 43137917 is a prime.

It is a super-2 number, since 2×43137981² = 3721770809512722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43137989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 798825 + ... + 798878.

It is an arithmetic number, because the mean of its divisors is an integer number (7988520).

Almost surely, 2^43137981 is an apocalyptic number.

It is an amenable number.

43137981 is a deficient number, since it is larger than the sum of its proper divisors (20770179).

43137981 is a wasteful number, since it uses less digits than its factorization.

43137981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1597712 (or 1597706 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 43137981 is about 6567.9510503657. The cubic root of 43137981 is about 350.7141364500.

The spelling of 43137981 in words is "forty-three million, one hundred thirty-seven thousand, nine hundred eighty-one".