1616537557221 has 4 divisors (see below), whose sum is σ = 2155383409632. Its totient is φ = 1077691704812.

The previous prime is 1616537557169. The next prime is 1616537557289. The reversal of 1616537557221 is 1227557356161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1616537557221 - 2¹⁷ = 1616537426149 is a prime.

It is a super-2 number, since 2×1616537557221² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1616537557321) 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 3 ways as a sum of consecutive naturals, for example, 269422926201 + ... + 269422926206.

It is an arithmetic number, because the mean of its divisors is an integer number (538845852408).

Almost surely, 2^{1616537557221} is an apocalyptic number.

It is an amenable number.

1616537557221 is a deficient number, since it is larger than the sum of its proper divisors (538845852411).

1616537557221 is an equidigital number, since it uses as much as digits as its factorization.

1616537557221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538845852410.

The product of its digits is 2646000, while the sum is 51.

The spelling of 1616537557221 in words is "one trillion, six hundred sixteen billion, five hundred thirty-seven million, five hundred fifty-seven thousand, two hundred twenty-one".