121551 has 8 divisors (see below), whose sum is σ = 167424. Its totient is φ = 78360.

The previous prime is 121547. The next prime is 121553. The reversal of 121551 is 155121.

121551 = 10² + 11² + ... + 71².

121551 is nontrivially palindromic in base 14.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 121551 - 2² = 121547 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 561 + ... + 746.

It is an arithmetic number, because the mean of its divisors is an integer number (20928).

2¹²¹⁵⁵¹ is an apocalyptic number.

121551 is the 221-st centered pentagonal number.

121551 is a deficient number, since it is larger than the sum of its proper divisors (45873).

121551 is a wasteful number, since it uses less digits than its factorization.

121551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1341.

The product of its digits is 50, while the sum is 15.

The square root of 121551 is about 348.6416498355. The cubic root of 121551 is about 49.5358377348.

Adding to 121551 its reverse (155121), we get a palindrome (276672).

The spelling of 121551 in words is "one hundred twenty-one thousand, five hundred fifty-one".