121515320551 has 4 divisors (see below), whose sum is σ = 121544058600. Its totient is φ = 121486582504.

The previous prime is 121515320539. The next prime is 121515320599. The reversal of 121515320551 is 155023515121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 155023515121 = 37 ⋅4189824733.

It is a cyclic number.

It is not a de Polignac number, because 121515320551 - 2¹⁷ = 121515189479 is a prime.

It is a super-2 number, since 2×121515320551² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121515320501) 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, 14362681 + ... + 14371138.

It is an arithmetic number, because the mean of its divisors is an integer number (30386014650).

Almost surely, 2^121515320551 is an apocalyptic number.

121515320551 is a deficient number, since it is larger than the sum of its proper divisors (28738049).

121515320551 is an equidigital number, since it uses as much as digits as its factorization.

121515320551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28738048.

The product of its (nonzero) digits is 7500, while the sum is 31.

Adding to 121515320551 its reverse (155023515121), we get a palindrome (276538835672).

The spelling of 121515320551 in words is "one hundred twenty-one billion, five hundred fifteen million, three hundred twenty thousand, five hundred fifty-one".