1661919229 has 4 divisors (see below), whose sum is σ = 1664903484. Its totient is φ = 1658934976.

The previous prime is 1661919221. The next prime is 1661919239. The reversal of 1661919229 is 9229191661.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 462336004 + 1199583225 = 21502^2 + 34635^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661919229 - 2³ = 1661919221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661919221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1491292 + ... + 1492405.

It is an arithmetic number, because the mean of its divisors is an integer number (416225871).

Almost surely, 2^1661919229 is an apocalyptic number.

It is an amenable number.

1661919229 is a deficient number, since it is larger than the sum of its proper divisors (2984255).

1661919229 is an equidigital number, since it uses as much as digits as its factorization.

1661919229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2984254.

The product of its digits is 104976, while the sum is 46.

The square root of 1661919229 is about 40766.6435827136. The cubic root of 1661919229 is about 1184.5042889740.

The spelling of 1661919229 in words is "one billion, six hundred sixty-one million, nine hundred nineteen thousand, two hundred twenty-nine".