1787406661 has 2 divisors, whose sum is σ = 1787406662. Its totient is φ = 1787406660.

The previous prime is 1787406629. The next prime is 1787406667. The reversal of 1787406661 is 1666047871.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1765260225 + 22146436 = 42015^2 + 4706^2 .

It is a cyclic number.

It is not a de Polignac number, because 1787406661 - 2⁵ = 1787406629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1787406667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 893703330 + 893703331.

It is an arithmetic number, because the mean of its divisors is an integer number (893703331).

Almost surely, 2^1787406661 is an apocalyptic number.

It is an amenable number.

1787406661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1787406661 is an equidigital number, since it uses as much as digits as its factorization.

1787406661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 338688, while the sum is 46.

The square root of 1787406661 is about 42277.7324486543. The cubic root of 1787406661 is about 1213.5968970083.

The spelling of 1787406661 in words is "one billion, seven hundred eighty-seven million, four hundred six thousand, six hundred sixty-one".