1020003561 has 12 divisors (see below), whose sum is σ = 1479948288. Its totient is φ = 676951704.

The previous prime is 1020003547. The next prime is 1020003577. The reversal of 1020003561 is 1653000201.

1020003561 is a `hidden beast` number, since 102 + 0 + 0 + 0 + 3 + 561 = 666.

It is not a de Polignac number, because 1020003561 - 2¹⁸ = 1019741417 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1020003661) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 252105 + ... + 256118.

It is an arithmetic number, because the mean of its divisors is an integer number (123329024).

Almost surely, 2^1020003561 is an apocalyptic number.

It is an amenable number.

1020003561 is a deficient number, since it is larger than the sum of its proper divisors (459944727).

1020003561 is a wasteful number, since it uses less digits than its factorization.

1020003561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 508452 (or 508449 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 1020003561 is about 31937.4945949115. The cubic root of 1020003561 is about 1006.6238809913.

Adding to 1020003561 its reverse (1653000201), we get a palindrome (2673003762).

The spelling of 1020003561 in words is "one billion, twenty million, three thousand, five hundred sixty-one".