1991423113680 has 1920 divisors, whose sum is σ = 8760015323136. Its totient is φ = 362946355200.

The previous prime is 1991423113679. The next prime is 1991423113741. The reversal of 1991423113680 is 863113241991.

It is a super-3 number, since 3×1991423113680³ (a number of 38 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 6486720087 + ... + 6486720393.

Almost surely, 2^{1991423113680} is an apocalyptic number.

1991423113680 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 1991423113680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4380007661568).

1991423113680 is an abundant number, since it is smaller than the sum of its proper divisors (6768592209456).

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

1991423113680 is a wasteful number, since it uses less digits than its factorization.

1991423113680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465 (or 446 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 48.

The spelling of 1991423113680 in words is "one trillion, nine hundred ninety-one billion, four hundred twenty-three million, one hundred thirteen thousand, six hundred eighty".