121672511551 has 4 divisors (see below), whose sum is σ = 121819282600. Its totient is φ = 121525740504.

The previous prime is 121672511489. The next prime is 121672511567. The reversal of 121672511551 is 155115276121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 155115276121 = 13 ⋅11931944317.

It is a cyclic number.

It is not a de Polignac number, because 121672511551 - 2⁹ = 121672511039 is a prime.

It is a super-4 number, since 4×121672511551⁴ (a number of 45 digits) contains 4444 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121672511551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121672581551) 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, 73384281 + ... + 73385938.

It is an arithmetic number, because the mean of its divisors is an integer number (30454820650).

Almost surely, 2^121672511551 is an apocalyptic number.

121672511551 is a deficient number, since it is larger than the sum of its proper divisors (146771049).

121672511551 is an equidigital number, since it uses as much as digits as its factorization.

121672511551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146771048.

The product of its digits is 21000, while the sum is 37.

Adding to 121672511551 its reverse (155115276121), we get a palindrome (276787787672).

The spelling of 121672511551 in words is "one hundred twenty-one billion, six hundred seventy-two million, five hundred eleven thousand, five hundred fifty-one".