7771191742921 has 4 divisors (see below), whose sum is σ = 7851307121812. Its totient is φ = 7691076364032.

The previous prime is 7771191742843. The next prime is 7771191742997. The reversal of 7771191742921 is 1292471911777.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2810166086025 + 4961025656896 = 1676355^2 + 2227336^2 .

It is a cyclic number.

It is not a de Polignac number, because 7771191742921 - 2⁷ = 7771191742793 is a prime.

It is a super-2 number, since 2×7771191742921² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7771191742121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40057689300 + ... + 40057689493.

It is an arithmetic number, because the mean of its divisors is an integer number (1962826780453).

Almost surely, 2^{7771191742921} is an apocalyptic number.

It is an amenable number.

7771191742921 is a deficient number, since it is larger than the sum of its proper divisors (80115378891).

7771191742921 is an equidigital number, since it uses as much as digits as its factorization.

7771191742921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80115378890.

The product of its digits is 3111696, while the sum is 58.

The spelling of 7771191742921 in words is "seven trillion, seven hundred seventy-one billion, one hundred ninety-one million, seven hundred forty-two thousand, nine hundred twenty-one".