821780085465 has 48 divisors (see below), whose sum is σ = 1472160807936. Its totient is φ = 423627350400.

The previous prime is 821780085461. The next prime is 821780085487. The reversal of 821780085465 is 564580087128.

821780085465 is a `hidden beast` number, since 8 + 2 + 17 + 80 + 0 + 8 + 546 + 5 = 666.

It is not a de Polignac number, because 821780085465 - 2² = 821780085461 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821780085461) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 786532 + ... + 1504058.

It is an arithmetic number, because the mean of its divisors is an integer number (30670016832).

Almost surely, 2^821780085465 is an apocalyptic number.

It is an amenable number.

821780085465 is a deficient number, since it is larger than the sum of its proper divisors (650380722471).

821780085465 is a wasteful number, since it uses less digits than its factorization.

821780085465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 718390 (or 718387 counting only the distinct ones).

The product of its (nonzero) digits is 4300800, while the sum is 54.

The spelling of 821780085465 in words is "eight hundred twenty-one billion, seven hundred eighty million, eighty-five thousand, four hundred sixty-five".