1644140745 has 48 divisors (see below), whose sum is σ = 3078238800. Its totient is φ = 807003648.

The previous prime is 1644140741. The next prime is 1644140749. The reversal of 1644140745 is 5470414461.

It is a happy number.

1644140745 is a `hidden beast` number, since 1 + 644 + 1 + 4 + 0 + 7 + 4 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (1644140741) and next prime (1644140749).

It can be written as a sum of positive squares in 8 ways, for example, as 441 + 1644140304 = 21^2 + 40548^2 .

It is not a de Polignac number, because 1644140745 - 2² = 1644140741 is a prime.

It is a super-3 number, since 3×1644140745³ (a number of 29 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (1644140741) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 200139 + ... + 208191.

It is an arithmetic number, because the mean of its divisors is an integer number (64129975).

Almost surely, 2^1644140745 is an apocalyptic number.

1644140745 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1644140745 is a deficient number, since it is larger than the sum of its proper divisors (1434098055).

1644140745 is a wasteful number, since it uses less digits than its factorization.

1644140745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8426 (or 8423 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The square root of 1644140745 is about 40548.0054379990. The cubic root of 1644140745 is about 1180.2653681159.

The spelling of 1644140745 in words is "one billion, six hundred forty-four million, one hundred forty thousand, seven hundred forty-five".