19973977937991 has 96 divisors (see below), whose sum is σ = 37430826301440. Its totient is φ = 9963011016000.

The previous prime is 19973977937983. The next prime is 19973977938119.

19973977937991 is a `hidden beast` number, since 19 + 9 + 73 + 9 + 7 + 79 + 379 + 91 = 666.

19973977937991 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 19973977937991 - 2³ = 19973977937983 is a prime.

It is a super-2 number, since 2×19973977937991² (a number of 27 digits) contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19973977937911) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3922285 + ... + 7438566.

It is an arithmetic number, because the mean of its divisors is an integer number (389904440640).

Almost surely, 2^{19973977937991} is an apocalyptic number.

19973977937991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

19973977937991 is a deficient number, since it is larger than the sum of its proper divisors (17456848363449).

19973977937991 is a wasteful number, since it uses less digits than its factorization.

19973977937991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11360977 (or 11360974 counting only the distinct ones).

The product of its digits is 11483908569, while the sum is 90.

The spelling of 19973977937991 in words is "nineteen trillion, nine hundred seventy-three billion, nine hundred seventy-seven million, nine hundred thirty-seven thousand, nine hundred ninety-one".