821971295655 has 32 divisors (see below), whose sum is σ = 1339972469760. Its totient is φ = 430179984000.

The previous prime is 821971295617. The next prime is 821971295659. The reversal of 821971295655 is 556592179128.

It is not a de Polignac number, because 821971295655 - 2⁹ = 821971295143 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821971295659) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1934596 + ... + 2320905.

It is an arithmetic number, because the mean of its divisors is an integer number (41874139680).

Almost surely, 2^821971295655 is an apocalyptic number.

821971295655 is a deficient number, since it is larger than the sum of its proper divisors (518001174105).

821971295655 is a wasteful number, since it uses less digits than its factorization.

821971295655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4255751.

The product of its digits is 13608000, while the sum is 60.

The spelling of 821971295655 in words is "eight hundred twenty-one billion, nine hundred seventy-one million, two hundred ninety-five thousand, six hundred fifty-five".