2091977498689 has 81 divisors (see below), whose sum is σ = 2430736763931. Its totient is φ = 1799511966720.

The previous prime is 2091977498659. The next prime is 2091977498707. The reversal of 2091977498689 is 9868947791902.

The square root of 2091977498689 is 1446367.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 1017869121025 + 1074108377664 = 1008895^2 + 1036392^2 .

It is not a de Polignac number, because 2091977498689 - 2¹⁹ = 2091976974401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2091977498659) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 21566778289 + ... + 21566778385.

It is an arithmetic number, because the mean of its divisors is an integer number (30009095851).

Almost surely, 2^{2091977498689} is an apocalyptic number.

2091977498689 is the 1446367-th square number.

2091977498689 is the 723184-th centered octagonal number.

It is an amenable number.

2091977498689 is a deficient number, since it is larger than the sum of its proper divisors (338759265242).

2091977498689 is an frugal number, since it uses more digits than its factorization.

2091977498689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 987614208, while the sum is 79.

The spelling of 2091977498689 in words is "two trillion, ninety-one billion, nine hundred seventy-seven million, four hundred ninety-eight thousand, six hundred eighty-nine".