1553554212221 has 4 divisors (see below), whose sum is σ = 1694786413344. Its totient is φ = 1412322011100.

The previous prime is 1553554212209. The next prime is 1553554212229. The reversal of 1553554212221 is 1222124553551.

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 not a de Polignac number, because 1553554212221 - 2³⁰ = 1552480470397 is a prime.

It is a super-2 number, since 2×1553554212221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1553554212229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70616100545 + ... + 70616100566.

It is an arithmetic number, because the mean of its divisors is an integer number (423696603336).

Almost surely, 2^{1553554212221} is an apocalyptic number.

1553554212221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1553554212221 is a deficient number, since it is larger than the sum of its proper divisors (141232201123).

1553554212221 is a wasteful number, since it uses less digits than its factorization.

1553554212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141232201122.

The product of its digits is 120000, while the sum is 38.

Adding to 1553554212221 its reverse (1222124553551), we get a palindrome (2775678765772).

The spelling of 1553554212221 in words is "one trillion, five hundred fifty-three billion, five hundred fifty-four million, two hundred twelve thousand, two hundred twenty-one".