121555363647 has 16 divisors (see below), whose sum is σ = 166104314208. Its totient is φ = 79023505920.

The previous prime is 121555363637. The next prime is 121555363649. The reversal of 121555363647 is 746363555121.

It is a happy number.

It is not a de Polignac number, because 121555363647 - 2²⁷ = 121421145919 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 121555363596 and 121555363605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121555363649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35313 + ... + 494325.

It is an arithmetic number, because the mean of its divisors is an integer number (10381519638).

Almost surely, 2^121555363647 is an apocalyptic number.

121555363647 is a deficient number, since it is larger than the sum of its proper divisors (44548950561).

121555363647 is a wasteful number, since it uses less digits than its factorization.

121555363647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 461210.

The product of its digits is 2268000, while the sum is 48.

It can be divided in two parts, 1215553 and 63647, that added together give a triangular number (1279200 = T₁₅₉₉).

The spelling of 121555363647 in words is "one hundred twenty-one billion, five hundred fifty-five million, three hundred sixty-three thousand, six hundred forty-seven".