27506491661 has 4 divisors (see below), whose sum is σ = 30007081824. Its totient is φ = 25005901500.

The previous prime is 27506491643. The next prime is 27506491687. The reversal of 27506491661 is 16619460572.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 27506491661 - 2¹⁴ = 27506475277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27506499661) 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, 1250295065 + ... + 1250295086.

It is an arithmetic number, because the mean of its divisors is an integer number (7501770456).

Almost surely, 2^27506491661 is an apocalyptic number.

It is an amenable number.

27506491661 is a deficient number, since it is larger than the sum of its proper divisors (2500590163).

27506491661 is a wasteful number, since it uses less digits than its factorization.

27506491661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2500590162.

The product of its (nonzero) digits is 544320, while the sum is 47.

The spelling of 27506491661 in words is "twenty-seven billion, five hundred six million, four hundred ninety-one thousand, six hundred sixty-one".