155387421857 has 4 divisors (see below), whose sum is σ = 155388394260. Its totient is φ = 155386449456.

The previous prime is 155387421853. The next prime is 155387421863. The reversal of 155387421857 is 758124783551.

155387421857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 52767143521 + 102620278336 = 229711^2 + 320344^2 .

It is a cyclic number.

It is not a de Polignac number, because 155387421857 - 2² = 155387421853 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155387421853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 183818 + ... + 586995.

It is an arithmetic number, because the mean of its divisors is an integer number (38847098565).

Almost surely, 2^155387421857 is an apocalyptic number.

It is an amenable number.

155387421857 is a deficient number, since it is larger than the sum of its proper divisors (972403).

155387421857 is an equidigital number, since it uses as much as digits as its factorization.

155387421857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 972402.

The product of its digits is 9408000, while the sum is 56.

The spelling of 155387421857 in words is "one hundred fifty-five billion, three hundred eighty-seven million, four hundred twenty-one thousand, eight hundred fifty-seven".