81284666657 has 8 divisors (see below), whose sum is σ = 82126196640. Its totient is φ = 80447441760.

The previous prime is 81284666633. The next prime is 81284666681. The reversal of 81284666657 is 75666648218.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81284666633) and next prime (81284666681).

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 81284666657 - 2⁸ = 81284666401 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81284666596 and 81284666605.

It is not an unprimeable number, because it can be changed into a prime (81284666857) 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, 1038308 + ... + 1113845.

It is an arithmetic number, because the mean of its divisors is an integer number (10265774580).

Almost surely, 2^81284666657 is an apocalyptic number.

It is an amenable number.

81284666657 is a deficient number, since it is larger than the sum of its proper divisors (841529983).

81284666657 is a wasteful number, since it uses less digits than its factorization.

81284666657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2152543.

The product of its digits is 23224320, while the sum is 59.

The spelling of 81284666657 in words is "eighty-one billion, two hundred eighty-four million, six hundred sixty-six thousand, six hundred fifty-seven".