155040721920 has 704 divisors, whose sum is σ = 641792471040. Its totient is φ = 34757738496.

The previous prime is 155040721907. The next prime is 155040721921. The reversal of 155040721920 is 29127040551.

155040721920 is a `hidden beast` number, since 1 + 550 + 4 + 0 + 72 + 19 + 20 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (155040721921) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 51285529 + ... + 51288551.

Almost surely, 2^155040721920 is an apocalyptic number.

155040721920 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 155040721920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320896235520).

155040721920 is an abundant number, since it is smaller than the sum of its proper divisors (486751749120).

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

155040721920 is a wasteful number, since it uses less digits than its factorization.

155040721920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3117 (or 3093 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The spelling of 155040721920 in words is "one hundred fifty-five billion, forty million, seven hundred twenty-one thousand, nine hundred twenty".