121451551561 has 4 divisors (see below), whose sum is σ = 122255866624. Its totient is φ = 120647236500.

The previous prime is 121451551553. The next prime is 121451551601. The reversal of 121451551561 is 165155154121.

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 an emirpimes, since its reverse is a distinct semiprime: 165155154121 = 89 ⋅1855675889.

It is a cyclic number.

It is not a de Polignac number, because 121451551561 - 2³ = 121451551553 is a prime.

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 121451551561.

It is not an unprimeable number, because it can be changed into a prime (121451521561) 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, 402157305 + ... + 402157606.

It is an arithmetic number, because the mean of its divisors is an integer number (30563966656).

Almost surely, 2^121451551561 is an apocalyptic number.

It is an amenable number.

121451551561 is a deficient number, since it is larger than the sum of its proper divisors (804315063).

121451551561 is an equidigital number, since it uses as much as digits as its factorization.

121451551561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 804315062.

The product of its digits is 30000, while the sum is 37.

The spelling of 121451551561 in words is "one hundred twenty-one billion, four hundred fifty-one million, five hundred fifty-one thousand, five hundred sixty-one".