991277705087 has 8 divisors (see below), whose sum is σ = 995779389840. Its totient is φ = 986777524800.

The previous prime is 991277705083. The next prime is 991277705107. The reversal of 991277705087 is 780507772199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 991277705087 - 2² = 991277705083 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 (991277705083) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 955328 + ... + 1701530.

It is an arithmetic number, because the mean of its divisors is an integer number (124472423730).

Almost surely, 2^991277705087 is an apocalyptic number.

991277705087 is a deficient number, since it is larger than the sum of its proper divisors (4501684753).

991277705087 is a wasteful number, since it uses less digits than its factorization.

991277705087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 752233.

The product of its (nonzero) digits is 15558480, while the sum is 62.

The spelling of 991277705087 in words is "nine hundred ninety-one billion, two hundred seventy-seven million, seven hundred five thousand, eighty-seven".