155665001 has 4 divisors (see below), whose sum is σ = 155696772. Its totient is φ = 155633232.

The previous prime is 155664983. The next prime is 155665009. The reversal of 155665001 is 100566551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 100566551 = 43 ⋅2338757.

It can be written as a sum of positive squares in 2 ways, for example, as 46566976 + 109098025 = 6824^2 + 10445^2 .

It is a cyclic number.

It is not a de Polignac number, because 155665001 - 2¹⁸ = 155402857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155665009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6806 + ... + 18911.

It is an arithmetic number, because the mean of its divisors is an integer number (38924193).

Almost surely, 2^155665001 is an apocalyptic number.

It is an amenable number.

155665001 is a deficient number, since it is larger than the sum of its proper divisors (31771).

155665001 is an equidigital number, since it uses as much as digits as its factorization.

155665001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31770.

The product of its (nonzero) digits is 4500, while the sum is 29.

The square root of 155665001 is about 12476.5780965776. The cubic root of 155665001 is about 537.9356494022.

The spelling of 155665001 in words is "one hundred fifty-five million, six hundred sixty-five thousand, one".