1521561427221 has 32 divisors (see below), whose sum is σ = 2216533372416. Its totient is φ = 920762024000.

The previous prime is 1521561427219. The next prime is 1521561427259. The reversal of 1521561427221 is 1227241651251.

It is a cyclic number.

It is not a de Polignac number, because 1521561427221 - 2¹ = 1521561427219 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1521561427221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1521561427261) 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, 120647206 + ... + 120659816.

It is an arithmetic number, because the mean of its divisors is an integer number (69266667888).

Almost surely, 2^{1521561427221} is an apocalyptic number.

1521561427221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1521561427221 is a deficient number, since it is larger than the sum of its proper divisors (694971945195).

1521561427221 is a wasteful number, since it uses less digits than its factorization.

1521561427221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17873.

The product of its digits is 67200, while the sum is 39.

The spelling of 1521561427221 in words is "one trillion, five hundred twenty-one billion, five hundred sixty-one million, four hundred twenty-seven thousand, two hundred twenty-one".