1644069157 has 4 divisors (see below), whose sum is σ = 1644175456. Its totient is φ = 1643962860.

The previous prime is 1644069109. The next prime is 1644069173. The reversal of 1644069157 is 7519604461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1644069157 - 2⁷ = 1644069029 is a prime.

It is a super-3 number, since 3×1644069157³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644069197) 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, 24969 + ... + 62542.

It is an arithmetic number, because the mean of its divisors is an integer number (411043864).

Almost surely, 2^1644069157 is an apocalyptic number.

It is an amenable number.

1644069157 is a deficient number, since it is larger than the sum of its proper divisors (106299).

1644069157 is an equidigital number, since it uses as much as digits as its factorization.

1644069157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106298.

The product of its (nonzero) digits is 181440, while the sum is 43.

The square root of 1644069157 is about 40547.1226722686. The cubic root of 1644069157 is about 1180.2482377772.

The spelling of 1644069157 in words is "one billion, six hundred forty-four million, sixty-nine thousand, one hundred fifty-seven".