1788912661 has 2 divisors, whose sum is σ = 1788912662. Its totient is φ = 1788912660.

The previous prime is 1788912623. The next prime is 1788912673. The reversal of 1788912661 is 1662198871.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1195015761 + 593896900 = 34569^2 + 24370^2 .

It is a cyclic number.

It is not a de Polignac number, because 1788912661 - 2²¹ = 1786815509 is a prime.

It is a super-2 number, since 2×1788912661² = 6400417017372201842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1788912611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 894456330 + 894456331.

It is an arithmetic number, because the mean of its divisors is an integer number (894456331).

Almost surely, 2^1788912661 is an apocalyptic number.

It is an amenable number.

1788912661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1788912661 is an equidigital number, since it uses as much as digits as its factorization.

1788912661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290304, while the sum is 49.

The square root of 1788912661 is about 42295.5394929536. The cubic root of 1788912661 is about 1213.9376446581.

The spelling of 1788912661 in words is "one billion, seven hundred eighty-eight million, nine hundred twelve thousand, six hundred sixty-one".