19901734381 has 4 divisors (see below), whose sum is σ = 20439619132. Its totient is φ = 19363849632.

The previous prime is 19901734367. The next prime is 19901734393. The reversal of 19901734381 is 18343710991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14057896356 + 5843838025 = 118566^2 + 76445^2 .

It is a cyclic number.

It is not a de Polignac number, because 19901734381 - 2⁹ = 19901733869 is a prime.

It is a super-2 number, since 2×19901734381² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19901734481) 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 3 ways as a sum of consecutive naturals, for example, 268942320 + ... + 268942393.

It is an arithmetic number, because the mean of its divisors is an integer number (5109904783).

Almost surely, 2^19901734381 is an apocalyptic number.

It is an amenable number.

19901734381 is a deficient number, since it is larger than the sum of its proper divisors (537884751).

19901734381 is an equidigital number, since it uses as much as digits as its factorization.

19901734381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 537884750.

The product of its (nonzero) digits is 163296, while the sum is 46.

It can be divided in two parts, 1990 and 1734381, that added together give a palindrome (1736371).

The spelling of 19901734381 in words is "nineteen billion, nine hundred one million, seven hundred thirty-four thousand, three hundred eighty-one".