27800881661 has 16 divisors (see below), whose sum is σ = 32384880000. Its totient is φ = 23370355008.

The previous prime is 27800881657. The next prime is 27800881721. The reversal of 27800881661 is 16618800872.

It is a happy number.

It is not a de Polignac number, because 27800881661 - 2² = 27800881657 is a prime.

It is a super-2 number, since 2×27800881661² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27800881621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1006250 + ... + 1033508.

It is an arithmetic number, because the mean of its divisors is an integer number (2024055000).

Almost surely, 2^27800881661 is an apocalyptic number.

It is an amenable number.

27800881661 is a deficient number, since it is larger than the sum of its proper divisors (4583998339).

27800881661 is a wasteful number, since it uses less digits than its factorization.

27800881661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30068.

The product of its (nonzero) digits is 258048, while the sum is 47.

The spelling of 27800881661 in words is "twenty-seven billion, eight hundred million, eight hundred eighty-one thousand, six hundred sixty-one".