987777722222221 has 16 divisors (see below), whose sum is σ = 1144662593655424. Its totient is φ = 834842567268864.

The previous prime is 987777722222197. The next prime is 987777722222261. The reversal of 987777722222221 is 122222227777789.

It is not a de Polignac number, because 987777722222221 - 2⁹ = 987777722221709 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (987777722222261) 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, 259542915 + ... + 263321248.

It is an arithmetic number, because the mean of its divisors is an integer number (71541412103464).

Almost surely, 2^{987777722222221} is an apocalyptic number.

It is an amenable number.

987777722222221 is a deficient number, since it is larger than the sum of its proper divisors (156884871433203).

987777722222221 is a wasteful number, since it uses less digits than its factorization.

987777722222221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522867940.

The product of its digits is 154893312, while the sum is 67.

The spelling of 987777722222221 in words is "nine hundred eighty-seven trillion, seven hundred seventy-seven billion, seven hundred twenty-two million, two hundred twenty-two thousand, two hundred twenty-one".