155780640 has 144 divisors (see below), whose sum is σ = 534957696. Its totient is φ = 41280000.

The previous prime is 155780629. The next prime is 155780671. The reversal of 155780640 is 46087551.

155780640 is a `hidden beast` number, since 1 + 5 + 5 + 7 + 8 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 155780595 and 155780604.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 361225 + ... + 361655.

It is an arithmetic number, because the mean of its divisors is an integer number (3714984).

Almost surely, 2^155780640 is an apocalyptic number.

155780640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 155780640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (267478848).

155780640 is an abundant number, since it is smaller than the sum of its proper divisors (379177056).

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

155780640 is a wasteful number, since it uses less digits than its factorization.

155780640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 703 (or 692 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The square root of 155780640 is about 12481.2114796601. The cubic root of 155780640 is about 538.0688220116.

The spelling of 155780640 in words is "one hundred fifty-five million, seven hundred eighty thousand, six hundred forty".