1771820649 has 21 divisors (see below), whose sum is σ = 2658220813. Its totient is φ = 1180456092.

The previous prime is 1771820551. The next prime is 1771820651. The reversal of 1771820649 is 9460281771.

It is a happy number.

The square root of 1771820649 is 42093.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 1771820649 - 2¹³ = 1771812457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1771820669) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 1135732 + ... + 1137290.

Almost surely, 2^1771820649 is an apocalyptic number.

1771820649 is the 42093-rd square number.

1771820649 is the 21047-th centered octagonal number.

It is an amenable number.

1771820649 is a deficient number, since it is larger than the sum of its proper divisors (886400164).

1771820649 is an frugal number, since it uses more digits than its factorization.

1771820649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3136 (or 1562 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The cubic root of 1771820649 is about 1210.0591116991.

The spelling of 1771820649 in words is "one billion, seven hundred seventy-one million, eight hundred twenty thousand, six hundred forty-nine".