9999777644 has 6 divisors (see below), whose sum is σ = 17499610884. Its totient is φ = 4999888820.

The previous prime is 9999777629. The next prime is 9999777673. The reversal of 9999777644 is 4467779999.

It is a nialpdrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1249972202 + ... + 1249972209.

It is an arithmetic number, because the mean of its divisors is an integer number (2916601814).

Almost surely, 2^9999777644 is an apocalyptic number.

It is an amenable number.

9999777644 is a deficient number, since it is larger than the sum of its proper divisors (7499833240).

9999777644 is a wasteful number, since it uses less digits than its factorization.

9999777644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2499944415 (or 2499944413 counting only the distinct ones).

The product of its digits is 216040608, while the sum is 71.

The square root of 9999777644 is about 99998.8882138197. Note that the first 3 decimals coincide. The cubic root of 9999777644 is about 2154.4187215309.

The spelling of 9999777644 in words is "nine billion, nine hundred ninety-nine million, seven hundred seventy-seven thousand, six hundred forty-four".