155531640 has 256 divisors, whose sum is σ = 559872000. Its totient is φ = 34119680.

The previous prime is 155531603. The next prime is 155531647. The reversal of 155531640 is 46135551.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 155531598 and 155531607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155531647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 650641 + ... + 650879.

It is an arithmetic number, because the mean of its divisors is an integer number (2187000).

Almost surely, 2^155531640 is an apocalyptic number.

155531640 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 155531640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (279936000).

155531640 is an abundant number, since it is smaller than the sum of its proper divisors (404340360).

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

155531640 is a wasteful number, since it uses less digits than its factorization.

155531640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310 (or 306 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 30.

The square root of 155531640 is about 12471.2324972314. The cubic root of 155531640 is about 537.7819858034.

The spelling of 155531640 in words is "one hundred fifty-five million, five hundred thirty-one thousand, six hundred forty".