1561551203 has 4 divisors (see below), whose sum is σ = 1577012208. Its totient is φ = 1546090200.

The previous prime is 1561551161. The next prime is 1561551217. The reversal of 1561551203 is 3021551651.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561551203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561551223) 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, 7730351 + ... + 7730552.

It is an arithmetic number, because the mean of its divisors is an integer number (394253052).

Almost surely, 2^1561551203 is an apocalyptic number.

1561551203 is a deficient number, since it is larger than the sum of its proper divisors (15461005).

1561551203 is a wasteful number, since it uses less digits than its factorization.

1561551203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15461004.

The product of its (nonzero) digits is 4500, while the sum is 29.

The square root of 1561551203 is about 39516.4674914143. The cubic root of 1561551203 is about 1160.1622848160.

The spelling of 1561551203 in words is "one billion, five hundred sixty-one million, five hundred fifty-one thousand, two hundred three".