81007943 has 4 divisors (see below), whose sum is σ = 82033440. Its totient is φ = 79982448.

The previous prime is 81007919. The next prime is 81007973. The reversal of 81007943 is 34970018.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34970018 = 2 ⋅17485009.

It is a cyclic number.

It is not a de Polignac number, because 81007943 - 2⁸ = 81007687 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 (81007973) 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, 512630 + ... + 512787.

It is an arithmetic number, because the mean of its divisors is an integer number (20508360).

Almost surely, 2^81007943 is an apocalyptic number.

81007943 is a deficient number, since it is larger than the sum of its proper divisors (1025497).

81007943 is a wasteful number, since it uses less digits than its factorization.

81007943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1025496.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 81007943 is about 9000.4412669602. The cubic root of 81007943 is about 432.6890135785.

The spelling of 81007943 in words is "eighty-one million, seven thousand, nine hundred forty-three".