121656081555 has 48 divisors (see below), whose sum is σ = 218561859360. Its totient is φ = 62525299200.

The previous prime is 121656081553. The next prime is 121656081571. The reversal of 121656081555 is 555180656121.

121656081555 is a `hidden beast` number, since 1 + 2 + 1 + 6 + 560 + 81 + 5 + 5 + 5 = 666.

It is not a de Polignac number, because 121656081555 - 2¹ = 121656081553 is a prime.

It is a super-2 number, since 2×121656081555² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 121656081555.

It is not an unprimeable number, because it can be changed into a prime (121656081553) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 590440 + ... + 769370.

It is an arithmetic number, because the mean of its divisors is an integer number (4553372070).

Almost surely, 2^121656081555 is an apocalyptic number.

121656081555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

121656081555 is a deficient number, since it is larger than the sum of its proper divisors (96905777805).

121656081555 is a wasteful number, since it uses less digits than its factorization.

121656081555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179492 (or 179489 counting only the distinct ones).

The product of its (nonzero) digits is 360000, while the sum is 45.

The spelling of 121656081555 in words is "one hundred twenty-one billion, six hundred fifty-six million, eighty-one thousand, five hundred fifty-five".