187731424561 has 4 divisors (see below), whose sum is σ = 189840766500. Its totient is φ = 185622082624.

The previous prime is 187731424549. The next prime is 187731424577. The reversal of 187731424561 is 165424137781.

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

It can be written as a sum of positive squares in 2 ways, for example, as 17260704400 + 170470720161 = 131380^2 + 412881^2 .

It is a cyclic number.

It is not a de Polignac number, because 187731424561 - 2¹⁷ = 187731293489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (187731424591) 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, 1054670836 + ... + 1054671013.

It is an arithmetic number, because the mean of its divisors is an integer number (47460191625).

Almost surely, 2^187731424561 is an apocalyptic number.

It is an amenable number.

187731424561 is a deficient number, since it is larger than the sum of its proper divisors (2109341939).

187731424561 is an equidigital number, since it uses as much as digits as its factorization.

187731424561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2109341938.

The product of its digits is 1128960, while the sum is 49.

The spelling of 187731424561 in words is "one hundred eighty-seven billion, seven hundred thirty-one million, four hundred twenty-four thousand, five hundred sixty-one".