155489216778 has 36 divisors (see below), whose sum is σ = 391896293490. Its totient is φ = 44425490256.

The previous prime is 155489216723. The next prime is 155489216803. The reversal of 155489216778 is 877612984551.

155489216778 is a `hidden beast` number, since 1 + 5 + 5 + 489 + 21 + 67 + 78 = 666.

155489216778 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 151798289769 + 3690927009 = 389613^2 + 60753^2 .

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 88144933 + ... + 88146696.

Almost surely, 2^155489216778 is an apocalyptic number.

155489216778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

155489216778 is an abundant number, since it is smaller than the sum of its proper divisors (236407076712).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

155489216778 is a wasteful number, since it uses less digits than its factorization.

155489216778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176291651 (or 176291641 counting only the distinct ones).

The product of its digits is 33868800, while the sum is 63.

The spelling of 155489216778 in words is "one hundred fifty-five billion, four hundred eighty-nine million, two hundred sixteen thousand, seven hundred seventy-eight".