1644065642025 has 48 divisors (see below), whose sum is σ = 3020466648000. Its totient is φ = 876760346880.

The previous prime is 1644065641993. The next prime is 1644065642029. The reversal of 1644065642025 is 5202465604461.

1644065642025 is a `hidden beast` number, since 1 + 6 + 4 + 40 + 6 + 564 + 20 + 25 = 666.

It is not a de Polignac number, because 1644065642025 - 2⁵ = 1644065641993 is a prime.

It is a super-3 number, since 3×1644065642025³ (a number of 38 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (1644065642029) 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, 8338026 + ... + 8532924.

It is an arithmetic number, because the mean of its divisors is an integer number (62926388500).

Almost surely, 2^{1644065642025} is an apocalyptic number.

1644065642025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1644065642025 is a deficient number, since it is larger than the sum of its proper divisors (1376401005975).

1644065642025 is a wasteful number, since it uses less digits than its factorization.

1644065642025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207415 (or 207404 counting only the distinct ones).

The product of its (nonzero) digits is 1382400, while the sum is 45.

The spelling of 1644065642025 in words is "one trillion, six hundred forty-four billion, sixty-five million, six hundred forty-two thousand, twenty-five".