155681363909 has 4 divisors (see below), whose sum is σ = 156212699916. Its totient is φ = 155150027904.

The previous prime is 155681363881. The next prime is 155681363939. The reversal of 155681363909 is 909363186551.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 142121460100 + 13559903809 = 376990^2 + 116447^2 .

It is a cyclic number.

It is not a de Polignac number, because 155681363909 - 2²⁸ = 155412928453 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 (155681363939) 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, 265667564 + ... + 265668149.

It is an arithmetic number, because the mean of its divisors is an integer number (39053174979).

Almost surely, 2^155681363909 is an apocalyptic number.

It is an amenable number.

155681363909 is a deficient number, since it is larger than the sum of its proper divisors (531336007).

155681363909 is an equidigital number, since it uses as much as digits as its factorization.

155681363909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 531336006.

The product of its (nonzero) digits is 5248800, while the sum is 56.

The spelling of 155681363909 in words is "one hundred fifty-five billion, six hundred eighty-one million, three hundred sixty-three thousand, nine hundred nine".