155781978 has 32 divisors (see below), whose sum is σ = 341019072. Its totient is φ = 47049600.

The previous prime is 155781973. The next prime is 155781979. The reversal of 155781978 is 879187551.

155781978 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 155781978.

It is not an unprimeable number, because it can be changed into a prime (155781973) 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, 16888 + ... + 24428.

It is an arithmetic number, because the mean of its divisors is an integer number (10656846).

Almost surely, 2^155781978 is an apocalyptic number.

155781978 is an abundant number, since it is smaller than the sum of its proper divisors (185237094).

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

155781978 is a wasteful number, since it uses less digits than its factorization.

155781978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7870.

The product of its digits is 705600, while the sum is 51.

The square root of 155781978 is about 12481.2650801111. The cubic root of 155781978 is about 538.0703624984.

The spelling of 155781978 in words is "one hundred fifty-five million, seven hundred eighty-one thousand, nine hundred seventy-eight".