155661621412443 has 4 divisors (see below), whose sum is σ = 207548828549928. Its totient is φ = 103774414274960.

The previous prime is 155661621412387. The next prime is 155661621412489. The reversal of 155661621412443 is 344214126166551.

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

It is a cyclic number.

It is not a de Polignac number, because 155661621412443 - 2¹² = 155661621408347 is a prime.

It is not an unprimeable number, because it can be changed into a prime (155661621512443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25943603568738 + ... + 25943603568743.

It is an arithmetic number, because the mean of its divisors is an integer number (51887207137482).

Almost surely, 2^{155661621412443} is an apocalyptic number.

155661621412443 is a deficient number, since it is larger than the sum of its proper divisors (51887207137485).

155661621412443 is an equidigital number, since it uses as much as digits as its factorization.

155661621412443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51887207137484.

The product of its digits is 4147200, while the sum is 51.

Adding to 155661621412443 its reverse (344214126166551), we get a palindrome (499875747578994).

The spelling of 155661621412443 in words is "one hundred fifty-five trillion, six hundred sixty-one billion, six hundred twenty-one million, four hundred twelve thousand, four hundred forty-three".