81782007 has 4 divisors (see below), whose sum is σ = 109042680. Its totient is φ = 54521336.

The previous prime is 81781991. The next prime is 81782027. The reversal of 81782007 is 70028718.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81782007 - 2⁴ = 81781991 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81782027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13630332 + ... + 13630337.

It is an arithmetic number, because the mean of its divisors is an integer number (27260670).

Almost surely, 2^81782007 is an apocalyptic number.

81782007 is a deficient number, since it is larger than the sum of its proper divisors (27260673).

81782007 is a wasteful number, since it uses less digits than its factorization.

81782007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27260672.

The product of its (nonzero) digits is 6272, while the sum is 33.

The square root of 81782007 is about 9043.3404779429. The cubic root of 81782007 is about 434.0628205128.

The spelling of 81782007 in words is "eighty-one million, seven hundred eighty-two thousand, seven".