1661673623040 has 640 divisors, whose sum is σ = 6078189363840. Its totient is φ = 429981696000.

The previous prime is 1661673623033. The next prime is 1661673623041. The reversal of 1661673623040 is 403263761661.

1661673623040 is a `hidden beast` number, since 1 + 6 + 6 + 16 + 7 + 3 + 623 + 0 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a super-2 number, since 2×1661673623040² (a number of 25 digits) contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661673623041) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1383574440 + ... + 1383575640.

It is an arithmetic number, because the mean of its divisors is an integer number (9497170881).

Almost surely, 2^{1661673623040} is an apocalyptic number.

1661673623040 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 1661673623040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3039094681920).

1661673623040 is an abundant number, since it is smaller than the sum of its proper divisors (4416515740800).

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

1661673623040 is a wasteful number, since it uses less digits than its factorization.

1661673623040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1811 (or 1789 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 45.

The spelling of 1661673623040 in words is "one trillion, six hundred sixty-one billion, six hundred seventy-three million, six hundred twenty-three thousand, forty".