187020656681 has 4 divisors (see below), whose sum is σ = 187111755012. Its totient is φ = 186929558352.

The previous prime is 187020656659. The next prime is 187020656687. The reversal of 187020656681 is 186656020781.

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 64321075456 + 122699581225 = 253616^2 + 350285^2 .

It is a cyclic number.

It is not a de Polignac number, because 187020656681 - 2¹⁸ = 187020394537 is a prime.

It is a super-2 number, since 2×187020656681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (187020656687) 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, 45546086 + ... + 45550191.

It is an arithmetic number, because the mean of its divisors is an integer number (46777938753).

Almost surely, 2^187020656681 is an apocalyptic number.

It is an amenable number.

187020656681 is a deficient number, since it is larger than the sum of its proper divisors (91098331).

187020656681 is an equidigital number, since it uses as much as digits as its factorization.

187020656681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91098330.

The product of its (nonzero) digits is 967680, while the sum is 50.

The spelling of 187020656681 in words is "one hundred eighty-seven billion, twenty million, six hundred fifty-six thousand, six hundred eighty-one".