7779291649 has 4 divisors (see below), whose sum is σ = 7784545860. Its totient is φ = 7774037440.

The previous prime is 7779291607. The next prime is 7779291697. The reversal of 7779291649 is 9461929777.

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 4063170049 + 3716121600 = 63743^2 + 60960^2 .

It is a cyclic number.

It is not a de Polignac number, because 7779291649 - 2¹¹ = 7779289601 is a prime.

It is a super-2 number, since 2×7779291649² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7779292649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2624884 + ... + 2627845.

It is an arithmetic number, because the mean of its divisors is an integer number (1946136465).

Almost surely, 2^7779291649 is an apocalyptic number.

It is an amenable number.

7779291649 is a deficient number, since it is larger than the sum of its proper divisors (5254211).

7779291649 is a wasteful number, since it uses less digits than its factorization.

7779291649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5254210.

The product of its digits is 12002256, while the sum is 61.

The square root of 7779291649 is about 88200.2927942986. The cubic root of 7779291649 is about 1981.4358568540.

The spelling of 7779291649 in words is "seven billion, seven hundred seventy-nine million, two hundred ninety-one thousand, six hundred forty-nine".