121553681 has 4 divisors (see below), whose sum is σ = 121575792. Its totient is φ = 121531572.

The previous prime is 121553669. The next prime is 121553683. The reversal of 121553681 is 186355121.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 121553681 - 2⁶ = 121553617 is a prime.

It is a super-3 number, since 3×121553681³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121553683) 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, 4310 + ... + 16176.

It is an arithmetic number, because the mean of its divisors is an integer number (30393948).

Almost surely, 2^121553681 is an apocalyptic number.

It is an amenable number.

121553681 is a deficient number, since it is larger than the sum of its proper divisors (22111).

121553681 is a wasteful number, since it uses less digits than its factorization.

121553681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22110.

The product of its digits is 7200, while the sum is 32.

The square root of 121553681 is about 11025.1385932332. The cubic root of 121553681 is about 495.3620192926.

The spelling of 121553681 in words is "one hundred twenty-one million, five hundred fifty-three thousand, six hundred eighty-one".