19936398691 has 16 divisors (see below), whose sum is σ = 22064088960. Its totient is φ = 17863054720.

The previous prime is 19936398673. The next prime is 19936398709. The reversal of 19936398691 is 19689363991.

It is an interprime number because it is at equal distance from previous prime (19936398673) and next prime (19936398709).

It is a cyclic number.

It is not a de Polignac number, because 19936398691 - 2¹¹ = 19936396643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19936398791) 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, 177696 + ... + 267298.

It is an arithmetic number, because the mean of its divisors is an integer number (1379005560).

Almost surely, 2^19936398691 is an apocalyptic number.

19936398691 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

19936398691 is a deficient number, since it is larger than the sum of its proper divisors (2127690269).

19936398691 is a wasteful number, since it uses less digits than its factorization.

19936398691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89906.

The product of its digits is 17006112, while the sum is 64.

The spelling of 19936398691 in words is "nineteen billion, nine hundred thirty-six million, three hundred ninety-eight thousand, six hundred ninety-one".