1561993553 has 16 divisors (see below), whose sum is σ = 1676280000. Its totient is φ = 1451043072.

The previous prime is 1561993547. The next prime is 1561993561. The reversal of 1561993553 is 3553991651.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-1561993553 is a prime.

It is a super-2 number, since 2×1561993553² = 4879647719227127618, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1561993498 and 1561993507.

It is not an unprimeable number, because it can be changed into a prime (1561993513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 510773 + ... + 513821.

It is an arithmetic number, because the mean of its divisors is an integer number (104767500).

Almost surely, 2^1561993553 is an apocalyptic number.

It is an amenable number.

1561993553 is a deficient number, since it is larger than the sum of its proper divisors (114286447).

1561993553 is a wasteful number, since it uses less digits than its factorization.

1561993553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3584.

The product of its digits is 546750, while the sum is 47.

The square root of 1561993553 is about 39522.0641287876. The cubic root of 1561993553 is about 1160.2718231892.

The spelling of 1561993553 in words is "one billion, five hundred sixty-one million, nine hundred ninety-three thousand, five hundred fifty-three".