121656556849 has 9 divisors (see below), whose sum is σ = 124014117409. Its totient is φ = 119343012880.

The previous prime is 121656556841. The next prime is 121656556873. The reversal of 121656556849 is 948655656121.

The square root of 121656556849 is 348793.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 251698225 + 121404858624 = 15865^2 + 348432^2 .

It is not a de Polignac number, because 121656556849 - 2³ = 121656556841 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 121656556793 and 121656556802.

It is not an unprimeable number, because it can be changed into a prime (121656556841) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 18482739 + ... + 18489319.

Almost surely, 2^121656556849 is an apocalyptic number.

121656556849 is the 348793-rd square number.

121656556849 is the 174397-th centered octagonal number.

It is an amenable number.

121656556849 is a deficient number, since it is larger than the sum of its proper divisors (2357560560).

121656556849 is an frugal number, since it uses more digits than its factorization.

121656556849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13268 (or 6634 counting only the distinct ones).

The product of its digits is 15552000, while the sum is 58.

The spelling of 121656556849 in words is "one hundred twenty-one billion, six hundred fifty-six million, five hundred fifty-six thousand, eight hundred forty-nine".