1561221652 has 12 divisors (see below), whose sum is σ = 2742528096. Its totient is φ = 777642200.

The previous prime is 1561221637. The next prime is 1561221653. The reversal of 1561221652 is 2561221651.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561221653) 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, 740974 + ... + 743077.

It is an arithmetic number, because the mean of its divisors is an integer number (228544008).

Almost surely, 2^1561221652 is an apocalyptic number.

It is an amenable number.

1561221652 is a deficient number, since it is larger than the sum of its proper divisors (1181306444).

1561221652 is a wasteful number, since it uses less digits than its factorization.

1561221652 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1484318 (or 1484316 counting only the distinct ones).

The product of its digits is 7200, while the sum is 31.

The square root of 1561221652 is about 39512.2974781270. The cubic root of 1561221652 is about 1160.0806652189.

Subtracting 1561221652 from its reverse (2561221651), we obtain a palindrome (999999999).

The spelling of 1561221652 in words is "one billion, five hundred sixty-one million, two hundred twenty-one thousand, six hundred fifty-two".