19956657124816 has 10 divisors (see below), whose sum is σ = 38666023179362. Its totient is φ = 9978328562400.

The previous prime is 19956657124783. The next prime is 19956657124823. The reversal of 19956657124816 is 61842175665991.

It can be written as a sum of positive squares in only one way, i.e., 11955136064400 + 8001521060416 = 3457620^2 + 2828696^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 623645535135 + ... + 623645535166.

Almost surely, 2^{19956657124816} is an apocalyptic number.

19956657124816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

19956657124816 is a deficient number, since it is larger than the sum of its proper divisors (18709366054546).

19956657124816 is a wasteful number, since it uses less digits than its factorization.

19956657124816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1247291070309 (or 1247291070303 counting only the distinct ones).

The product of its digits is 195955200, while the sum is 70.

The spelling of 19956657124816 in words is "nineteen trillion, nine hundred fifty-six billion, six hundred fifty-seven million, one hundred twenty-four thousand, eight hundred sixteen".