155491749 has 18 divisors (see below), whose sum is σ = 261269190. Its totient is φ = 88852176.

The previous prime is 155491747. The next prime is 155491759. The reversal of 155491749 is 947194551.

155491749 is a `hidden beast` number, since 1 + 554 + 91 + 7 + 4 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 153512100 + 1979649 = 12390^2 + 1407^2 .

It is not a de Polignac number, because 155491749 - 2¹ = 155491747 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155491747) 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 17 ways as a sum of consecutive naturals, for example, 175854 + ... + 176735.

It is an arithmetic number, because the mean of its divisors is an integer number (14514955).

Almost surely, 2^155491749 is an apocalyptic number.

It is an amenable number.

155491749 is a deficient number, since it is larger than the sum of its proper divisors (105777441).

155491749 is a wasteful number, since it uses less digits than its factorization.

155491749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352609 (or 352599 counting only the distinct ones).

The product of its digits is 226800, while the sum is 45.

The square root of 155491749 is about 12469.6330739922. The cubic root of 155491749 is about 537.7360048152.

It can be divided in two parts, 1554917 and 49, that added together give a triangular number (1554966 = T₁₇₆₃).

The spelling of 155491749 in words is "one hundred fifty-five million, four hundred ninety-one thousand, seven hundred forty-nine".