780309961 has 2 divisors, whose sum is σ = 780309962. Its totient is φ = 780309960.

The previous prime is 780309883. The next prime is 780309967. The reversal of 780309961 is 169903087.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 644144400 + 136165561 = 25380^2 + 11669^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-780309961 is a prime.

It is not a weakly prime, because it can be changed into another prime (780309967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390154980 + 390154981.

It is an arithmetic number, because the mean of its divisors is an integer number (390154981).

Almost surely, 2^780309961 is an apocalyptic number.

It is an amenable number.

780309961 is a deficient number, since it is larger than the sum of its proper divisors (1).

780309961 is an equidigital number, since it uses as much as digits as its factorization.

780309961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 780309961 is about 27934.0287284165. The cubic root of 780309961 is about 920.6383255166.

The spelling of 780309961 in words is "seven hundred eighty million, three hundred nine thousand, nine hundred sixty-one".