19862968190521 has 3 divisors (see below), whose sum is σ = 19862972647311. Its totient is φ = 19862963733732.

The previous prime is 19862968190497. The next prime is 19862968190567. The reversal of 19862968190521 is 12509186926891.

The square root of 19862968190521 is 4456789.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 5703551780521 + 14159416410000 = 2388211^2 + 3762900^2 .

It is not a de Polignac number, because 19862968190521 - 2³¹ = 19860820706873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19862968190581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2228395 + ... + 6685183.

It is an arithmetic number, because the mean of its divisors is an integer number (6620990882437).

Almost surely, 2^{19862968190521} is an apocalyptic number.

19862968190521 is the 4456789-th square number.

19862968190521 is the 2228395-th centered octagonal number.

It is an amenable number.

19862968190521 is a deficient number, since it is larger than the sum of its proper divisors (4456790).

19862968190521 is an frugal number, since it uses more digits than its factorization.

19862968190521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8913578 (or 4456789 counting only the distinct ones).

The product of its (nonzero) digits is 33592320, while the sum is 67.

The spelling of 19862968190521 in words is "nineteen trillion, eight hundred sixty-two billion, nine hundred sixty-eight million, one hundred ninety thousand, five hundred twenty-one".