689221961 has 2 divisors, whose sum is σ = 689221962. Its totient is φ = 689221960.

The previous prime is 689221943. The next prime is 689221969. The reversal of 689221961 is 169122986.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 648975625 + 40246336 = 25475^2 + 6344^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-689221961 is a prime.

It is not a weakly prime, because it can be changed into another prime (689221969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344610980 + 344610981.

It is an arithmetic number, because the mean of its divisors is an integer number (344610981).

Almost surely, 2^689221961 is an apocalyptic number.

It is an amenable number.

689221961 is a deficient number, since it is larger than the sum of its proper divisors (1).

689221961 is an equidigital number, since it uses as much as digits as its factorization.

689221961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 44.

The square root of 689221961 is about 26253.0371766773. The cubic root of 689221961 is about 883.3233327771.

The spelling of 689221961 in words is "six hundred eighty-nine million, two hundred twenty-one thousand, nine hundred sixty-one".