81550465 has 8 divisors (see below), whose sum is σ = 101235240. Its totient is φ = 62990592.

The previous prime is 81550463. The next prime is 81550477. The reversal of 81550465 is 56405518.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 18045504 + 63504961 = 4248^2 + 7969^2 .

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 81550465 - 2¹ = 81550463 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81550465.

It is not an unprimeable number, because it can be changed into a prime (81550463) 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, 281064 + ... + 281353.

It is an arithmetic number, because the mean of its divisors is an integer number (12654405).

Almost surely, 2^81550465 is an apocalyptic number.

It is an amenable number.

81550465 is a deficient number, since it is larger than the sum of its proper divisors (19684775).

81550465 is a wasteful number, since it uses less digits than its factorization.

81550465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 562451.

The product of its (nonzero) digits is 24000, while the sum is 34.

The square root of 81550465 is about 9030.5296079466. The cubic root of 81550465 is about 433.6527923749.

The spelling of 81550465 in words is "eighty-one million, five hundred fifty thousand, four hundred sixty-five".