1209764981 has 2 divisors, whose sum is σ = 1209764982. Its totient is φ = 1209764980.

The previous prime is 1209764917. The next prime is 1209765001. The reversal of 1209764981 is 1894679021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1068963025 + 140801956 = 32695^2 + 11866^2 .

It is a cyclic number.

It is not a de Polignac number, because 1209764981 - 2⁶ = 1209764917 is a prime.

It is a super-2 number, since 2×1209764981² = 2927062618507860722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1209764911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 604882490 + 604882491.

It is an arithmetic number, because the mean of its divisors is an integer number (604882491).

Almost surely, 2^1209764981 is an apocalyptic number.

It is an amenable number.

1209764981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1209764981 is an equidigital number, since it uses as much as digits as its factorization.

1209764981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 217728, while the sum is 47.

The square root of 1209764981 is about 34781.6759371943. The cubic root of 1209764981 is about 1065.5332414531.

The spelling of 1209764981 in words is "one billion, two hundred nine million, seven hundred sixty-four thousand, nine hundred eighty-one".