999997776 has 30 divisors (see below), whose sum is σ = 2798605290. Its totient is φ = 333332544.

The previous prime is 999997771. The next prime is 999997787. The reversal of 999997776 is 677799999.

It can be written as a sum of positive squares in only one way, i.e., 977187600 + 22810176 = 31260^2 + 4776^2 .

It is a Harshad number since it is a multiple of its sum of digits (72).

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 (999997771) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3472071 + ... + 3472358.

It is an arithmetic number, because the mean of its divisors is an integer number (93286843).

Almost surely, 2^999997776 is an apocalyptic number.

It is an amenable number.

999997776 is an abundant number, since it is smaller than the sum of its proper divisors (1798607514).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999997776 is a wasteful number, since it uses less digits than its factorization.

999997776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6944443 (or 6944434 counting only the distinct ones).

The product of its digits is 121522842, while the sum is 72.

The square root of 999997776 is about 31622.7414371367. The cubic root of 999997776 is about 999.9992586661. Note that the first 3 decimals are identical.

The spelling of 999997776 in words is "nine hundred ninety-nine million, nine hundred ninety-seven thousand, seven hundred seventy-six".