121201115551 has 4 divisors (see below), whose sum is σ = 121225394752. Its totient is φ = 121176836352.

The previous prime is 121201115527. The next prime is 121201115557. The reversal of 121201115551 is 155511102121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 121201115551 - 2¹³ = 121201107359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121201115557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12132111 + ... + 12142096.

It is an arithmetic number, because the mean of its divisors is an integer number (30306348688).

Almost surely, 2^121201115551 is an apocalyptic number.

121201115551 is a deficient number, since it is larger than the sum of its proper divisors (24279201).

121201115551 is an equidigital number, since it uses as much as digits as its factorization.

121201115551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24279200.

The product of its (nonzero) digits is 500, while the sum is 25.

Adding to 121201115551 its reverse (155511102121), we get a palindrome (276712217672).

The spelling of 121201115551 in words is "one hundred twenty-one billion, two hundred one million, one hundred fifteen thousand, five hundred fifty-one".