7821521602921 has 16 divisors (see below), whose sum is σ = 8436869376768. Its totient is φ = 7208138246400.

The previous prime is 7821521602883. The next prime is 7821521603047. The reversal of 7821521602921 is 1292061251287.

It is not a de Polignac number, because 7821521602921 - 2¹³ = 7821521594729 is a prime.

It is a super-2 number, since 2×7821521602921² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7821521602621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22411441 + ... + 22757761.

It is an arithmetic number, because the mean of its divisors is an integer number (527304336048).

Almost surely, 2^{7821521602921} is an apocalyptic number.

It is an amenable number.

7821521602921 is a deficient number, since it is larger than the sum of its proper divisors (615347773847).

7821521602921 is a wasteful number, since it uses less digits than its factorization.

7821521602921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 349152.

The product of its (nonzero) digits is 241920, while the sum is 46.

The spelling of 7821521602921 in words is "seven trillion, eight hundred twenty-one billion, five hundred twenty-one million, six hundred two thousand, nine hundred twenty-one".