19861730575921 has 16 divisors (see below), whose sum is σ = 21636421062480. Its totient is φ = 18122430965760.

The previous prime is 19861730575909. The next prime is 19861730575937. The reversal of 19861730575921 is 12957503716891.

It can be written as a sum of positive squares in 8 ways, for example, as 1244706160896 + 18617024415025 = 1115664^2 + 4314745^2 .

It is not a de Polignac number, because 19861730575921 - 2¹³ = 19861730567729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19861730575961) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1242351 + ... + 6423931.

It is an arithmetic number, because the mean of its divisors is an integer number (1352276316405).

Almost surely, 2^{19861730575921} is an apocalyptic number.

It is an amenable number.

19861730575921 is a deficient number, since it is larger than the sum of its proper divisors (1774690486559).

19861730575921 is a wasteful number, since it uses less digits than its factorization.

19861730575921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5184996.

The product of its (nonzero) digits is 28576800, while the sum is 64.

The spelling of 19861730575921 in words is "nineteen trillion, eight hundred sixty-one billion, seven hundred thirty million, five hundred seventy-five thousand, nine hundred twenty-one".