21940038613 has 4 divisors (see below), whose sum is σ = 22475161548. Its totient is φ = 21404915680.

The previous prime is 21940038607. The next prime is 21940038649. The reversal of 21940038613 is 31683004912.

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 12193018084 + 9747020529 = 110422^2 + 98727^2 .

It is a cyclic number.

It is not a de Polignac number, because 21940038613 - 2⁵ = 21940038581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21940038683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 267561406 + ... + 267561487.

It is an arithmetic number, because the mean of its divisors is an integer number (5618790387).

Almost surely, 2^21940038613 is an apocalyptic number.

It is an amenable number.

21940038613 is a deficient number, since it is larger than the sum of its proper divisors (535122935).

21940038613 is an equidigital number, since it uses as much as digits as its factorization.

21940038613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 535122934.

The product of its (nonzero) digits is 31104, while the sum is 37.

The spelling of 21940038613 in words is "twenty-one billion, nine hundred forty million, thirty-eight thousand, six hundred thirteen".