1764664661 has 2 divisors, whose sum is σ = 1764664662. Its totient is φ = 1764664660.

The previous prime is 1764664607. The next prime is 1764664709. The reversal of 1764664661 is 1664664671.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1305376900 + 459287761 = 36130^2 + 21431^2 .

It is an emirp because it is prime and its reverse (1664664671) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1764664661 is a prime.

It is a super-2 number, since 2×1764664661² = 6228082731564489842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1764664861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 882332330 + 882332331.

It is an arithmetic number, because the mean of its divisors is an integer number (882332331).

Almost surely, 2^1764664661 is an apocalyptic number.

It is an amenable number.

1764664661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1764664661 is an equidigital number, since it uses as much as digits as its factorization.

1764664661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 47.

The square root of 1764664661 is about 42007.9118857389. The cubic root of 1764664661 is about 1208.4278607788.

The spelling of 1764664661 in words is "one billion, seven hundred sixty-four million, six hundred sixty-four thousand, six hundred sixty-one".