5538187561 has 3 divisors (see below), whose sum is σ = 5538261981. Its totient is φ = 5538113142.

The previous prime is 5538187531. The next prime is 5538187573. The reversal of 5538187561 is 1657818355.

The square root of 5538187561 is 74419.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1657818355 = 5 ⋅331563671.

It is not a de Polignac number, because 5538187561 - 2²⁵ = 5504633129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5538187531) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 37210 + ... + 111628.

It is an arithmetic number, because the mean of its divisors is an integer number (1846087327).

Almost surely, 2^5538187561 is an apocalyptic number.

5538187561 is the 74419-th square number.

5538187561 is the 37210-th centered octagonal number.

It is an amenable number.

5538187561 is a deficient number, since it is larger than the sum of its proper divisors (74420).

5538187561 is an frugal number, since it uses more digits than its factorization.

5538187561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148838 (or 74419 counting only the distinct ones).

The product of its digits is 1008000, while the sum is 49.

The cubic root of 5538187561 is about 1769.2500638445.

Multiplying 5538187561 by its sum of digits (49), we get a square (271371190489 = 520933²).

The spelling of 5538187561 in words is "five billion, five hundred thirty-eight million, one hundred eighty-seven thousand, five hundred sixty-one".