1644251161 has 8 divisors (see below), whose sum is σ = 1879813440. Its totient is φ = 1408856208.

The previous prime is 1644251143. The next prime is 1644251173. The reversal of 1644251161 is 1611524461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1644251161 is a prime.

It is a super-3 number, since 3×1644251161³ (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 (1644251111) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20011 + ... + 60736.

It is an arithmetic number, because the mean of its divisors is an integer number (234976680).

Almost surely, 2^1644251161 is an apocalyptic number.

It is an amenable number.

1644251161 is a deficient number, since it is larger than the sum of its proper divisors (235562279).

1644251161 is an equidigital number, since it uses as much as digits as its factorization.

1644251161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83663.

The product of its digits is 5760, while the sum is 31.

The square root of 1644251161 is about 40549.3669617665. The cubic root of 1644251161 is about 1180.2917886568.

The spelling of 1644251161 in words is "one billion, six hundred forty-four million, two hundred fifty-one thousand, one hundred sixty-one".