155542121 has 24 divisors (see below), whose sum is σ = 186489864. Its totient is φ = 129292800.

The previous prime is 155542111. The next prime is 155542133. The reversal of 155542121 is 121245551.

It can be written as a sum of positive squares in 4 ways, for example, as 89038096 + 66504025 = 9436^2 + 8155^2 .

It is not a de Polignac number, because 155542121 - 2¹⁰ = 155541097 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 (155542111) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 262001 + ... + 262593.

It is an arithmetic number, because the mean of its divisors is an integer number (7770411).

Almost surely, 2^155542121 is an apocalyptic number.

It is an amenable number.

155542121 is a deficient number, since it is larger than the sum of its proper divisors (30947743).

155542121 is a wasteful number, since it uses less digits than its factorization.

155542121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 761 (or 754 counting only the distinct ones).

The product of its digits is 2000, while the sum is 26.

The square root of 155542121 is about 12471.6526972170. The cubic root of 155542121 is about 537.7940655886.

Adding to 155542121 its reverse (121245551), we get a palindrome (276787672).

The spelling of 155542121 in words is "one hundred fifty-five million, five hundred forty-two thousand, one hundred twenty-one".