1231780866 has 32 divisors (see below), whose sum is σ = 2625125760. Its totient is φ = 383974656.

The previous prime is 1231780831. The next prime is 1231780867. The reversal of 1231780866 is 6680871321.

It is not an unprimeable number, because it can be changed into a prime (1231780867) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22446 + ... + 54473.

It is an arithmetic number, because the mean of its divisors is an integer number (82035180).

Almost surely, 2^1231780866 is an apocalyptic number.

1231780866 is an abundant number, since it is smaller than the sum of its proper divisors (1393344894).

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

1231780866 is a wasteful number, since it uses less digits than its factorization.

1231780866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77098.

The product of its (nonzero) digits is 96768, while the sum is 42.

The square root of 1231780866 is about 35096.7358311282. The cubic root of 1231780866 is about 1071.9581187924.

The spelling of 1231780866 in words is "one billion, two hundred thirty-one million, seven hundred eighty thousand, eight hundred sixty-six".