866820947 has 4 divisors (see below), whose sum is σ = 869644776. Its totient is φ = 863997120.

The previous prime is 866820923. The next prime is 866820949. The reversal of 866820947 is 749028668.

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

It is a cyclic number.

It is not a de Polignac number, because 866820947 - 2¹² = 866816851 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 866820895 and 866820904.

It is not an unprimeable number, because it can be changed into a prime (866820949) 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, 1411454 + ... + 1412067.

It is an arithmetic number, because the mean of its divisors is an integer number (217411194).

Almost surely, 2^866820947 is an apocalyptic number.

866820947 is a deficient number, since it is larger than the sum of its proper divisors (2823829).

866820947 is a wasteful number, since it uses less digits than its factorization.

866820947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2823828.

The product of its (nonzero) digits is 1161216, while the sum is 50.

The square root of 866820947 is about 29441.8230923290. The cubic root of 866820947 is about 953.4760732064.

The spelling of 866820947 in words is "eight hundred sixty-six million, eight hundred twenty thousand, nine hundred forty-seven".