821278657512 has 32 divisors (see below), whose sum is σ = 2281329604800. Its totient is φ = 273759552432.

The previous prime is 821278657453. The next prime is 821278657543. The reversal of 821278657512 is 215756872128.

It is a happy number.

821278657512 is a `hidden beast` number, since 8 + 2 + 1 + 2 + 78 + 6 + 57 + 512 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 1901107788 + ... + 1901108219.

It is an arithmetic number, because the mean of its divisors is an integer number (71291550150).

Almost surely, 2^821278657512 is an apocalyptic number.

It is an amenable number.

821278657512 is an abundant number, since it is smaller than the sum of its proper divisors (1460050947288).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821278657512 is a wasteful number, since it uses less digits than its factorization.

821278657512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3802216022 (or 3802216012 counting only the distinct ones).

The product of its digits is 3763200, while the sum is 54.

The spelling of 821278657512 in words is "eight hundred twenty-one billion, two hundred seventy-eight million, six hundred fifty-seven thousand, five hundred twelve".