21238379693 has 6 divisors (see below), whose sum is σ = 21699876846. Its totient is φ = 20786497112.

The previous prime is 21238379677. The next prime is 21238379707. The reversal of 21238379693 is 39697383212.

It can be written as a sum of positive squares in only one way, i.e., 10749957124 + 10488422569 = 103682^2 + 102413^2 .

It is not a de Polignac number, because 21238379693 - 2⁴ = 21238379677 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 (21238373693) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4805030 + ... + 4809447.

It is an arithmetic number, because the mean of its divisors is an integer number (3616646141).

Almost surely, 2^21238379693 is an apocalyptic number.

It is an amenable number.

21238379693 is a deficient number, since it is larger than the sum of its proper divisors (461497153).

21238379693 is an frugal number, since it uses more digits than its factorization.

21238379693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9614571 (or 9614524 counting only the distinct ones).

The product of its digits is 2939328, while the sum is 53.

The spelling of 21238379693 in words is "twenty-one billion, two hundred thirty-eight million, three hundred seventy-nine thousand, six hundred ninety-three".