780226661 has 4 divisors (see below), whose sum is σ = 793017324. Its totient is φ = 767436000.

The previous prime is 780226627. The next prime is 780226669. The reversal of 780226661 is 166622087.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166622087 = 109 ⋅1528643.

It can be written as a sum of positive squares in 2 ways, for example, as 299082436 + 481144225 = 17294^2 + 21935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-780226661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (780226669) 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, 6395240 + ... + 6395361.

It is an arithmetic number, because the mean of its divisors is an integer number (198254331).

Almost surely, 2^780226661 is an apocalyptic number.

It is an amenable number.

780226661 is a deficient number, since it is larger than the sum of its proper divisors (12790663).

780226661 is a wasteful number, since it uses less digits than its factorization.

780226661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12790662.

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 780226661 is about 27932.5376756212. The cubic root of 780226661 is about 920.6055642186.

The spelling of 780226661 in words is "seven hundred eighty million, two hundred twenty-six thousand, six hundred sixty-one".