994678781 has 4 divisors (see below), whose sum is σ = 994887612. Its totient is φ = 994469952.

The previous prime is 994678759. The next prime is 994678793. The reversal of 994678781 is 187876499.

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 644652100 + 350026681 = 25390^2 + 18709^2 .

It is a cyclic number.

It is not a de Polignac number, because 994678781 - 2¹⁴ = 994662397 is a prime.

It is a super-2 number, since 2×994678781² = 1978771754743291922, 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 994678781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (994678981) 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, 97100 + ... + 106853.

It is an arithmetic number, because the mean of its divisors is an integer number (248721903).

Almost surely, 2^994678781 is an apocalyptic number.

It is an amenable number.

994678781 is a deficient number, since it is larger than the sum of its proper divisors (208831).

994678781 is a wasteful number, since it uses less digits than its factorization.

994678781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208830.

The product of its digits is 6096384, while the sum is 59.

The square root of 994678781 is about 31538.5285167206. The cubic root of 994678781 is about 998.2231048470.

The spelling of 994678781 in words is "nine hundred ninety-four million, six hundred seventy-eight thousand, seven hundred eighty-one".