121657660805 has 4 divisors (see below), whose sum is σ = 145989192972. Its totient is φ = 97326128640.

The previous prime is 121657660783. The next prime is 121657660807. The reversal of 121657660805 is 508066756121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 508066756121 = 73 ⋅6959818577.

It can be written as a sum of positive squares in 2 ways, for example, as 26027046241 + 95630614564 = 161329^2 + 309242^2 .

It is not a de Polignac number, because 121657660805 - 2¹⁴ = 121657644421 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 121657660805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121657660807) 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, 12165766076 + ... + 12165766085.

It is an arithmetic number, because the mean of its divisors is an integer number (36497298243).

Almost surely, 2^121657660805 is an apocalyptic number.

It is an amenable number.

121657660805 is a deficient number, since it is larger than the sum of its proper divisors (24331532167).

121657660805 is an equidigital number, since it uses as much as digits as its factorization.

121657660805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24331532166.

The product of its (nonzero) digits is 604800, while the sum is 47.

The spelling of 121657660805 in words is "one hundred twenty-one billion, six hundred fifty-seven million, six hundred sixty thousand, eight hundred five".