81403765 has 8 divisors (see below), whose sum is σ = 99763200. Its totient is φ = 63737232.

The previous prime is 81403759. The next prime is 81403787. The reversal of 81403765 is 56730418.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81403765 - 2³ = 81403757 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81403765.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 172965 + ... + 173434.

It is an arithmetic number, because the mean of its divisors is an integer number (12470400).

Almost surely, 2^81403765 is an apocalyptic number.

It is an amenable number.

81403765 is a deficient number, since it is larger than the sum of its proper divisors (18359435).

81403765 is a wasteful number, since it uses less digits than its factorization.

81403765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346451.

The product of its (nonzero) digits is 20160, while the sum is 34.

The square root of 81403765 is about 9022.4035046101. The cubic root of 81403765 is about 433.3926056332.

The spelling of 81403765 in words is "eighty-one million, four hundred three thousand, seven hundred sixty-five".