1644899022400 has 336 divisors, whose sum is σ = 4265910964224. Its totient is φ = 623063992320.

The previous prime is 1644899022329. The next prime is 1644899022419. The reversal of 1644899022400 is 42209984461.

It is a happy number.

It is a super-3 number, since 3×1644899022400³ (a number of 38 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (49) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1862852359 + ... + 1862853241.

It is an arithmetic number, because the mean of its divisors is an integer number (12696163584).

Almost surely, 2^{1644899022400} is an apocalyptic number.

1644899022400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1644899022400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2132955482112).

1644899022400 is an abundant number, since it is smaller than the sum of its proper divisors (2621011941824).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1644899022400 is a wasteful number, since it uses less digits than its factorization.

1644899022400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1378 (or 1363 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 49.

The spelling of 1644899022400 in words is "one trillion, six hundred forty-four billion, eight hundred ninety-nine million, twenty-two thousand, four hundred".