996639881 has 4 divisors (see below), whose sum is σ = 1023576132. Its totient is φ = 969703632.

The previous prime is 996639871. The next prime is 996639883. The reversal of 996639881 is 188936699.

996639881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 768176656 + 228463225 = 27716^2 + 15115^2 .

It is a cyclic number.

It is not a de Polignac number, because 996639881 - 2⁶ = 996639817 is a prime.

It is a super-2 number, since 2×996639881² = 1986582104799388322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 996639881.

It is not an unprimeable number, because it can be changed into a prime (996639883) 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, 13468070 + ... + 13468143.

It is an arithmetic number, because the mean of its divisors is an integer number (255894033).

Almost surely, 2^996639881 is an apocalyptic number.

It is an amenable number.

996639881 is a deficient number, since it is larger than the sum of its proper divisors (26936251).

996639881 is a wasteful number, since it uses less digits than its factorization.

996639881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26936250.

The product of its digits is 5038848, while the sum is 59.

The square root of 996639881 is about 31569.6037510768. The cubic root of 996639881 is about 998.8787034974.

The spelling of 996639881 in words is "nine hundred ninety-six million, six hundred thirty-nine thousand, eight hundred eighty-one".