155401665 has 32 divisors (see below), whose sum is σ = 268821120. Its totient is φ = 76391424.

The previous prime is 155401661. The next prime is 155401669. The reversal of 155401665 is 566104551.

It is an interprime number because it is at equal distance from previous prime (155401661) and next prime (155401669).

It is not a de Polignac number, because 155401665 - 2² = 155401661 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (155401661) 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 31 ways as a sum of consecutive naturals, for example, 3177 + ... + 17913.

It is an arithmetic number, because the mean of its divisors is an integer number (8400660).

Almost surely, 2^155401665 is an apocalyptic number.

155401665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

155401665 is a deficient number, since it is larger than the sum of its proper divisors (113419455).

155401665 is a wasteful number, since it uses less digits than its factorization.

155401665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14801.

The product of its (nonzero) digits is 18000, while the sum is 33.

The square root of 155401665 is about 12466.0204155135. The cubic root of 155401665 is about 537.6321391365.

It can be divided in two parts, 15540 and 1665, that added together give a triangular number (17205 = T₁₈₅).

The spelling of 155401665 in words is "one hundred fifty-five million, four hundred one thousand, six hundred sixty-five".