155444023661 has 4 divisors (see below), whose sum is σ = 155461654524. Its totient is φ = 155426392800.

The previous prime is 155444023643. The next prime is 155444023681. The reversal of 155444023661 is 166320444551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166320444551 = 631 ⋅263582321.

It can be written as a sum of positive squares in 2 ways, for example, as 136673653636 + 18770370025 = 369694^2 + 137005^2 .

It is a cyclic number.

It is not a de Polignac number, because 155444023661 - 2³⁰ = 154370281837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155444023601) 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, 8802200 + ... + 8819841.

It is an arithmetic number, because the mean of its divisors is an integer number (38865413631).

Almost surely, 2^155444023661 is an apocalyptic number.

It is an amenable number.

155444023661 is a deficient number, since it is larger than the sum of its proper divisors (17630863).

155444023661 is an equidigital number, since it uses as much as digits as its factorization.

155444023661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17630862.

The product of its (nonzero) digits is 345600, while the sum is 41.

The spelling of 155444023661 in words is "one hundred fifty-five billion, four hundred forty-four million, twenty-three thousand, six hundred sixty-one".