1561355223 has 4 divisors (see below), whose sum is σ = 2081806968. Its totient is φ = 1040903480.

The previous prime is 1561355221. The next prime is 1561355303. The reversal of 1561355223 is 3225531651.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1561355223 - 2¹ = 1561355221 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561355221) 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, 260225868 + ... + 260225873.

It is an arithmetic number, because the mean of its divisors is an integer number (520451742).

Almost surely, 2^1561355223 is an apocalyptic number.

1561355223 is a deficient number, since it is larger than the sum of its proper divisors (520451745).

1561355223 is an equidigital number, since it uses as much as digits as its factorization.

1561355223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520451744.

The product of its digits is 27000, while the sum is 33.

The square root of 1561355223 is about 39513.9876879062. The cubic root of 1561355223 is about 1160.1137480113.

Adding to 1561355223 its reverse (3225531651), we get a palindrome (4786886874).

The spelling of 1561355223 in words is "one billion, five hundred sixty-one million, three hundred fifty-five thousand, two hundred twenty-three".