781961 has 2 divisors, whose sum is σ = 781962. Its totient is φ = 781960.

The previous prime is 781951. The next prime is 781967. The reversal of 781961 is 169187.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 672400 + 109561 = 820^2 + 331^2 .

It is a cyclic number.

It is not a de Polignac number, because 781961 - 2⁶ = 781897 is a prime.

It is a super-2 number, since 2×781961² = 1222926011042, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (781967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390980 + 390981.

It is an arithmetic number, because the mean of its divisors is an integer number (390981).

2⁷⁸¹⁹⁶¹ is an apocalyptic number.

It is an amenable number.

781961 is a deficient number, since it is larger than the sum of its proper divisors (1).

781961 is an equidigital number, since it uses as much as digits as its factorization.

781961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 32.

The square root of 781961 is about 884.2855873529. The cubic root of 781961 is about 92.1287186894.

The spelling of 781961 in words is "seven hundred eighty-one thousand, nine hundred sixty-one".