1645863861040 has 160 divisors (see below), whose sum is σ = 4430153594880. Its totient is φ = 556964508672.

The previous prime is 1645863861017. The next prime is 1645863861067. The reversal of 1645863861040 is 401683685461.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 208941582 + ... + 208949458.

It is an arithmetic number, because the mean of its divisors is an integer number (27688459968).

Almost surely, 2^{1645863861040} is an apocalyptic number.

1645863861040 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 1645863861040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2215076797440).

1645863861040 is an abundant number, since it is smaller than the sum of its proper divisors (2784289733840).

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

1645863861040 is a wasteful number, since it uses less digits than its factorization.

1645863861040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12699 (or 12693 counting only the distinct ones).

The product of its (nonzero) digits is 3317760, while the sum is 52.

The spelling of 1645863861040 in words is "one trillion, six hundred forty-five billion, eight hundred sixty-three million, eight hundred sixty-one thousand, forty".