1555253121 has 4 divisors (see below), whose sum is σ = 2073670832. Its totient is φ = 1036835412.

The previous prime is 1555253107. The next prime is 1555253137. The reversal of 1555253121 is 1213525551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1555253121 - 2²⁶ = 1488144257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1555253191) 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, 259208851 + ... + 259208856.

It is an arithmetic number, because the mean of its divisors is an integer number (518417708).

Almost surely, 2^1555253121 is an apocalyptic number.

It is an amenable number.

1555253121 is a deficient number, since it is larger than the sum of its proper divisors (518417711).

1555253121 is an equidigital number, since it uses as much as digits as its factorization.

1555253121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 518417710.

The product of its digits is 7500, while the sum is 30.

The square root of 1555253121 is about 39436.6976431851. The cubic root of 1555253121 is about 1158.6004526733.

Adding to 1555253121 its reverse (1213525551), we get a palindrome (2768778672).

The spelling of 1555253121 in words is "one billion, five hundred fifty-five million, two hundred fifty-three thousand, one hundred twenty-one".