1561533242 has 4 divisors (see below), whose sum is σ = 2342299866. Its totient is φ = 780766620.

The previous prime is 1561533229. The next prime is 1561533247. The reversal of 1561533242 is 2423351651.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2423351651 = 7 ⋅346193093.

It can be written as a sum of positive squares in only one way, i.e., 1202771761 + 358761481 = 34681^2 + 18941^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1561533199 and 1561533208.

It is not an unprimeable number, because it can be changed into a prime (1561533247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390383309 + ... + 390383312.

Almost surely, 2^1561533242 is an apocalyptic number.

1561533242 is a deficient number, since it is larger than the sum of its proper divisors (780766624).

1561533242 is an equidigital number, since it uses as much as digits as its factorization.

1561533242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 780766623.

The product of its digits is 21600, while the sum is 32.

The square root of 1561533242 is about 39516.2402310746. The cubic root of 1561533242 is about 1160.1578367273.

Adding to 1561533242 its reverse (2423351651), we get a palindrome (3984884893).

The spelling of 1561533242 in words is "one billion, five hundred sixty-one million, five hundred thirty-three thousand, two hundred forty-two".