155521361 has 6 divisors (see below), whose sum is σ = 157150710. Its totient is φ = 153908736.

The previous prime is 155521349. The next prime is 155521369. The reversal of 155521361 is 163125551.

It can be written as a sum of positive squares in 3 ways, for example, as 46444225 + 109077136 = 6815^2 + 10444^2 .

It is not a de Polignac number, because 155521361 - 2¹⁸ = 155259217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (155521369) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1145 + ... + 17673.

It is an arithmetic number, because the mean of its divisors is an integer number (26191785).

Almost surely, 2^155521361 is an apocalyptic number.

It is an amenable number.

155521361 is a deficient number, since it is larger than the sum of its proper divisors (1629349).

155521361 is an frugal number, since it uses more digits than its factorization.

155521361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16723 (or 16626 counting only the distinct ones).

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

The square root of 155521361 is about 12470.8203819957. The cubic root of 155521361 is about 537.7701383045.

The spelling of 155521361 in words is "one hundred fifty-five million, five hundred twenty-one thousand, three hundred sixty-one".