1964773661 has 2 divisors, whose sum is σ = 1964773662. Its totient is φ = 1964773660.

The previous prime is 1964773651. The next prime is 1964773709. The reversal of 1964773661 is 1663774691.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1162128100 + 802645561 = 34090^2 + 28331^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1964773661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1964773621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 982386830 + 982386831.

It is an arithmetic number, because the mean of its divisors is an integer number (982386831).

Almost surely, 2^1964773661 is an apocalyptic number.

It is an amenable number.

1964773661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1964773661 is an equidigital number, since it uses as much as digits as its factorization.

1964773661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1143072, while the sum is 50.

The square root of 1964773661 is about 44325.7674609250. The cubic root of 1964773661 is about 1252.4801236150.

The spelling of 1964773661 in words is "one billion, nine hundred sixty-four million, seven hundred seventy-three thousand, six hundred sixty-one".