1555520243 has 2 divisors, whose sum is σ = 1555520244. Its totient is φ = 1555520242.

The previous prime is 1555520237. The next prime is 1555520273. The reversal of 1555520243 is 3420255551.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1555520243 - 2²⁸ = 1287084787 is a prime.

It is not a weakly prime, because it can be changed into another prime (1555520233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 777760121 + 777760122.

It is an arithmetic number, because the mean of its divisors is an integer number (777760122).

Almost surely, 2^1555520243 is an apocalyptic number.

1555520243 is a deficient number, since it is larger than the sum of its proper divisors (1).

1555520243 is an equidigital number, since it uses as much as digits as its factorization.

1555520243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30000, while the sum is 32.

The square root of 1555520243 is about 39440.0842164415. The cubic root of 1555520243 is about 1158.6667805589. Note that the first 3 decimals are identical.

Adding to 1555520243 its reverse (3420255551), we get a palindrome (4975775794).

The spelling of 1555520243 in words is "one billion, five hundred fifty-five million, five hundred twenty thousand, two hundred forty-three".