1651719409 has 4 divisors (see below), whose sum is σ = 1652830180. Its totient is φ = 1650608640.

The previous prime is 1651719379. The next prime is 1651719497. The reversal of 1651719409 is 9049171561.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9049171561 = 463 ⋅19544647.

It can be written as a sum of positive squares in 2 ways, for example, as 970509409 + 681210000 = 31153^2 + 26100^2 .

It is a cyclic number.

It is not a de Polignac number, because 1651719409 - 2²⁷ = 1517501681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1651719499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 553152 + ... + 556129.

It is an arithmetic number, because the mean of its divisors is an integer number (413207545).

Almost surely, 2^1651719409 is an apocalyptic number.

It is an amenable number.

1651719409 is a deficient number, since it is larger than the sum of its proper divisors (1110771).

1651719409 is a wasteful number, since it uses less digits than its factorization.

1651719409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1110770.

The product of its (nonzero) digits is 68040, while the sum is 43.

The square root of 1651719409 is about 40641.3509741003. The cubic root of 1651719409 is about 1182.0760658997.

The spelling of 1651719409 in words is "one billion, six hundred fifty-one million, seven hundred nineteen thousand, four hundred nine".