821420029791 has 24 divisors (see below), whose sum is σ = 1189491732000. Its totient is φ = 546232004352.

The previous prime is 821420029783. The next prime is 821420029841. The reversal of 821420029791 is 197920024128.

It is not a de Polignac number, because 821420029791 - 2³ = 821420029783 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821420009791) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6693795 + ... + 6815403.

It is an arithmetic number, because the mean of its divisors is an integer number (49562155500).

Almost surely, 2^821420029791 is an apocalyptic number.

821420029791 is a deficient number, since it is larger than the sum of its proper divisors (368071702209).

821420029791 is a wasteful number, since it uses less digits than its factorization.

821420029791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123503 (or 123500 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The spelling of 821420029791 in words is "eight hundred twenty-one billion, four hundred twenty million, twenty-nine thousand, seven hundred ninety-one".