155491840 has 80 divisors (see below), whose sum is σ = 426124512. Its totient is φ = 53305344.

The previous prime is 155491837. The next prime is 155491841. The reversal of 155491840 is 48194551.

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 155491840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155491841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13582 + ... + 22258.

Almost surely, 2^155491840 is an apocalyptic number.

155491840 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 155491840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (213062256).

155491840 is an abundant number, since it is smaller than the sum of its proper divisors (270632672).

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

155491840 is an frugal number, since it uses more digits than its factorization.

155491840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8707 (or 8691 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 37.

The square root of 155491840 is about 12469.6367228560. The cubic root of 155491840 is about 537.7361097167.

The spelling of 155491840 in words is "one hundred fifty-five million, four hundred ninety-one thousand, eight hundred forty".