1821850729 has 4 divisors (see below), whose sum is σ = 1822015620. Its totient is φ = 1821685840.

The previous prime is 1821850721. The next prime is 1821850741. The reversal of 1821850729 is 9270581281.

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 1400780329 + 421070400 = 37427^2 + 20520^2 .

It is a cyclic number.

It is not a de Polignac number, because 1821850729 - 2³ = 1821850721 is a prime.

It is a super-3 number, since 3×1821850729³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1821850721) 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, 64582 + ... + 88399.

It is an arithmetic number, because the mean of its divisors is an integer number (455503905).

Almost surely, 2^1821850729 is an apocalyptic number.

It is an amenable number.

1821850729 is a deficient number, since it is larger than the sum of its proper divisors (164891).

1821850729 is a wasteful number, since it uses less digits than its factorization.

1821850729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164890.

The product of its (nonzero) digits is 80640, while the sum is 43.

The square root of 1821850729 is about 42683.1433823705. The cubic root of 1821850729 is about 1221.3428573469.

The spelling of 1821850729 in words is "one billion, eight hundred twenty-one million, eight hundred fifty thousand, seven hundred twenty-nine".